If you enjoy assault rifles I strongly recommend the sickle. It's one of the most accurate weapons in the game and effectively has infinite ammo. If your aim is decent you can drop most enemies before it overheats. You're not going to be topping the kill count, but that isn't the point of the game.

Someone else mentioned the Quasar/EAT and I cannot echo that loudly enough. I prefer the Quasar for bots due to the increased frequency that I find myself needing anti-tank but it's a little more difficult to use than the EAT.

Everyone wants to stick to the Autocannon meta but it really doesn't work for me and there are some jobs that other tools do better. I can take out dropships with the EAT all day long where as the Autocannon can only hope to knock the bots off the bottom at best. This also frees up you backpack for the shield generator, which IS a crutch but will allow you a ton of breathing room against the bots in particular.

For armor against the bots you really want the perk that reduces explosive damage. The bots' laser fire isn't all that bad but for whatever reason they have pinpoint accuracy with rockets.

I don't think that avoiding bot patrols is the right answer. You really want to avoid ACCIDENTALLY engaging bot patrols or engaging them before the team is prepared. If you can get the drop on a patrol it's almost trivial for a team of helldivers to wipe them out without triggering dropships.

This game really thrives on communication, so encouraging any kind of dialogue between your team members is the best way to improve how your missions go.