I want a case that won't contribute to my phone getting hot, so my battery will last a long time and i can take advantage of all those years if pixel 6 updates

Putting a traditional full case on the back of your phone is thermal insulation over one half of the heat transfer area available to your phone. That will undoubtedly make your battery run hotter than it otherwise would in many situations.

A "bumper" style case (which runs around the perimeter/edges of the phone but doesn't cover the back) will still protect your phone from drops without any of that thermal insulation. And for many wireless charging stands (like my tronsmart wc01) a bumper style case puts your phone closer to the charger than a regular case because the top of the charger stand touches the phone directly (the bumper case only pushes the phone out away from the charger at the bottom, but not at the top).

I have found two bumper style cases for the P6:

• Foluu for $10. It's pretty slim but it sticks out far enough all around so that if you drop the phone, the case would still contact any flat surface before the phone or camera bar. I have this one and I'm happy with it. (it works fine with my wireless chargers)
• Poetic for $26. It looks a little beefier for even better protection against drops. That same beefiness also means it moves your phone further away from the charger. I can't say for sure it would work with wireless chargers (it depends on the charger of course) but I think in general most chargers are ok with most cases these days.