Hey, fellow bi-cyclist! Unfortunately, I have no useful advice to offer as I'm not from US and not a very social person, but want to congratulate you on coming out! Best of everything to you!

is there maybe a way of thinking about dating preferences without actually dating?

That's an interesting thought. I feel like this question is at the heart of a lot of posts on forums like this, both by self-exploring bisexuals and by their supportive partners. There is not a one-size-fits-all answer. But we can brainstorm some options. Like:

• Explore your tastes through fiction and media. Are you into books, TV shows, movies, video games, podcasts, webcomics, internet memes, fan fiction? Lots of content out there, and lots of recommendation lists in blog posts and forum threads. Obviously, dating in real life doesn't work like in a romantic comedy or a game feature (sadly, you are not guaranteed a date just because you gifted someone your excess vegetables and the cookies you found while dumpster diving), but it still might give you a better idea of what you are looking for in a partner and in a relationship overall. Moreover, it gives you something low stakes to talk about, both to potential partners and to people you are coming out to (more on that below).
• Special shout-out to interactive media like video games. Wanna be a small town farmer who turns the heads of both the socially anxious goth-programmer and the romantic writer with the beach home, then end up with the jock? You can do that. Wanna go on a big adventurous journey, in northern-inspired dragon-land or radioactive wasteland or even in space, while you romance your increasingly realistic-looking companions through dialogue trees? You can do that. Wanna build a nice family home with color-coded furniture where your character and his husband can build a nice life for them and their growing family, at least until someone is trapped in a pool or eaten by a cowplant? You can do that. Whatever you wish, wish fulfillment is right around the corner (at least as long as you have a powerful enough computer or other gaming system, or find a way around that, like streaming). For more examples, the TV Tropes wiki has a page on games (and other media) with same-sex romance options.
• Media created by other people is one thing, but how about you creating something yourself? It doesn't have to be "good" in the sense that it would get a good grade by a teacher, or make money, or be considered high art. Write that short story where nothing really happens. Draw that stick-figure comic. Put that meme together. Daydream. Take the most silly, blatant self-insert premise and run with it. What if Mercutio from "Romeo and Juliet" didn't get killed in the feud between Montagues and Capulets because he left Verona as soon as he realized that wasn't a good environment for him? Well, maybe he would have landed in a new place, unsure where to go and how to progress in life, but maybe then he would have met this wizard/knight/superhero character (the one played by the good-looking actor in the live-action adaptation, of course) and they started a relationship where they epically fought crime and also went on romantic candlelight dinners together? And as Mercutio is a character from a theater play who has been portrayed by many different actors over the centuries, it is totally correct when his boyfriend compliments him for looking like you.
• Find ways to talk about your identity to real people, online or offline, that feel natural to you. Disclaimer, you know your surroundings best, so don't put yourself in an uncomfortable or dangerous situation. Find ways to acknowledge this as a part of yourself in your normal life, where it doesn't have to be a big life-altering coming-out talk or a romantic interaction. "Can you recommend a book with a queer male lead character, preferably something lighthearted, that one could gift to a friend or family member? So nothing overly depressing or creepy. Could also be a graphic novel." - "Hello fellow anonymous forum users, I'm thinking about subscribing to this game streaming service, does it have games with same-sex romance options that I might have overlooked? I know I am interested in games x, y, and z, are these a good fit for streaming to my mobile device? Can't afford more powerful hardware right now. Thanks for your help!" - "Oh, hi, supportive-but-clueless family member back home, yes, I am settling in here, no, I haven't met anyone yet, and actually, I don't want to talk about my anxieties about going or not going to a gay bar right now, anyway, I've explored the local library and bookstore and the people there were nice, and now I'm reading this cute coming-of-age story." - "Product review: the key chain and stickers look very well made and the pride flag colors come out just as great as in the product photos (I have the bi flag and the men loving men flag, specifically). Great purchase, totally recommended!" - "Inquiry: I'd like to commission a digital painting of that wizard-knight-superhero on a romantic date with my OC who looks like [description], can you do that? I obviously pay the going rate, I love the art on your profile!" - "Meme I made, to meme community of choice, press post!" Once you get comfortable with these types of interactions, it might get easier to talk to people you actually want to flirt with.

That's just my ideas, though.

Edits for fixing typos.

I usually just tell people I'm looking for friends first. If I find myself liking someone I usually tell them I'd like something more from the friendship and see if it's something their interested in. I'm polyam so this advice may differ for monogamous people.

Hi bro, welcome!

Consider signing up for a hookup app like Scruff. Be honest in your profile about where you are in your journey and what you're looking for. You can see a lot of a guy before deciding if you like him or not, then meet for a drink and see if it makes sense to do more. In my experience, most guys don't want to jump straight to intercourse, even if they're horny af.

Try not to be shy, start some conversations, and start learning what you are into. If you ever want to chat with another bro, message me any time!

I've talked a lot with my therapist about this and it's all very daunting. Making social mistakes as an adult is something that makes me deeply uncomfortable

What do you mean when you say think ‘about dating preferences without actually dating’?

See if there are any meetup or facebook groups focused on ENM or D/s in your area. Those communities have tons of bi people and tons of people who don't expect you to know exactly what you want.

Welcome to yourself and the community! I'm proud of you! I know in my neck of the woods we have a Pride committee that does community events, do you have something like that?

I think the US scene is very active with dating apps right now. There is a whole range of them. This should at least allow you to “think about dating preferences without actually dating,” just by looking at other people and reading what they have posted. Of course apps are not for everyone and they can give a distorted take so this is just one idea you can evaluate.