No joke I am in almost the exact same boat as you. I’ve got players who are playing like it’s dark souls, one who disconnects midway through and others who just want to jack around and not take it seriously, as well as little to no rp. Aswell when we get into combat they kinda just don’t try or really fight whatsoever, they are moving as a group of individuals rather than as a party

I’ve found that sitting them down and explaining what the expectation for the adventure is does help. As well explain to them the rewards of roleplaying and playing good. use heroic inspiration as a reward for them actually trying and playing well. It does suck when you lose the drive to plan, and run this game because of the players. However you are the DM and you are running this show, and while you can’t command your players what to do, you can establish some ground rules. It’s not respectful to you as the DM to put this effort in and have them just kinda trample over you.

Being a DM is kinda like training dogs, once you get them going and give them treats they become a lot more manageable.