You're overthinking it, the process should be :

How do you want to look / feel ➡️ What exercises will help you achieve that look / feel ➡️ Proceed to workout

Anything else is external and thus irrelevant

Obviously it's easier to say, you don't just ignore social stigma or anxiety by tomorrow morning, but focus on the process and your goals

If you think women (or men if that's what you prefer) don't like men with a developed ass then I've got news for you!

Your muscular structure is a complex network of overlapped and interconnected fibers:

They are all bound up with each other and your skeleton. What you should not do is neglect any muscle areas, because that creates a weakness in the system which will increase the strain on other parts of the system. The muscles support the bones - if you underdevelop some muscles, while overdeveloping others, it's actually possible to damage your bones when the stronger muscles pull on them. A balanced, holistic approach is best.

If you have a male body, then you have male muscular structure. If you develop those muscles, they will be masculine... by definition.

It sounds a bit like this is veering into aesthetic preferences, and as far as that's concerned, it's 2024 AD. I've stopped keeping track of all the different minute variations of body type and fashion that've come and gone through the years. I don't think anyone worth listening to in the modern day is going to give someone grief over whether they're a bear or a twink or a daddy or a femboy or whatever else the newest aesthetic is called. Fat ass, tight ass, no ass; live your life.

Come to think of it, there's probably a femboy workout guide.

Do anything that gets you in the gym! Please, please, please don’t ego lift and watch videos and read books on proper form. It only takes one slip up to screw everything up. I was lifting one day as a matter of habit, but shouldn’t have been because I was in a bad mental state that week and was over tired and exhausted from a long weekend before of hiking and manual labor. Got sloppy and lazy and been dealing with back issues ever since including multiple procedures and surgeries.

IMO: Not really. 

Working out is a discipline, and it comes back to having the correct form without getting injured.

Squats are really popular, but getting the right form is really important.

Many people get hurt when doing squats if they do not do them correctly. 

In my group, it is important to do upper body workouts so as not to look too skinny and weak, while also doing leg workouts so as not to have chicken legs.

We focus more on continuing to grow as much as we can while making sure not to get injured.

You won’t “catch” or “accidentally” get a Brazilian butt lift just from the gym. Its a surgical procedure?

edit also, grow up. you can say penis on the internet