I am in the same situation. I should note I have always prioritized my PC’s speed at the expense of heat. I personally just live with the heat… when it gets hot, I sweat a lot, but air conditioning is pretty much out of reach for me.
I have NEVER had a house with air conditioning in it, and i’ve always been able to run my PC at full speed, even on very hot days. How did I do this? A variety of ways, but most of them revolve around getting better airflow to my PC.
My most recent PC, I have built specifically to address this problem. And I do it with air cooling (no water cooling).
In my region Last summer we had a couple weeks where the temperature got up above 100f in the shade (37.7c). Yet my computer still chugged along with nary a slowdown.
This is my current build with a 5950x and a 3090.
Click the blue down arrow to expand this post and see pictures of what I built with the exact hardware included…
If you can not afford to build a new machine, here is a very simple solution. If you are using a tower PC, take the side panel off your computer. And get a standard box fan - and plunk it down blowing directly into your pc.
(not a joke picture you can easily do something like this and it works fine)
If you want a quieter fan, get a full size box fan meant to cool a room, and aim that directly into your pc at a slow speed. That will work fine too but it has to be right next to the open computer.
A good solution for this problem is with your next builds for your PC - get a good HIGH AIRFLOW case. Watch Gamers Nexus https://www.youtube.com/c/GamersNexus/videos and do a search on his channel for the best cases. You want something where the entire front is basically open with some sort of mesh covering and big fans.
Here is a video of his where he covers the type of case I am talking about.
The Fractal Meshify cases are decent too.