Is a home theater even worth it or doable?

If you are considering an 85" TV make sure to check out short throw projectors, they work great. Smaller footprint, bigger picture, more value:

https://www.digitaltrends.com/home-theater/best-short-throw-projectors/

You should get a receiver capable of 7 bed channels, 4 height channels and at least two subs like the new Onkyo, Denon, or Anthem.

Then start with as many speakers as you like and simply add as budget allows, no need to go all in at once. KEY- all speakers should be same brand and ideally same series. I prefer monitor speakers with subs instead or towers but YMMV.

As for HT speakers these THX Ultra2 by Klipsch would be at the top of my list to partner with a receiver. :

https://www.klipsch.com/products/thx-ultra2-home-theater-system

@waytoomuchstuff

Interesting comments, can you please post your system in your profile? You are spot on when you talk about power being key. In my my system I have one 500 watt multichannel amp that powers 4 satellite speakers in my height channels which are easy loads. Every other speaker is either active, being fed power by a 150 watt (woofer) and a also a 50 watt (tweeter) internal monoblock, or a dedicated two channel 100 watt amp (back surrounds). My Sunfire subs are being driven by a 1400 watt amp. When you add it all up that is about 6000 watts +- driving my 9.2.8 system. It isn't designed to sound loud, its designed to sound effortless.