[crosspost]
Like this can't be just me, right? Phone constantly disconnecting, being at 80°C, and battery draining is fucking annoying. Also the option to disable 5G is gone, wtf, big tech?!?
Not all phones support all the bands (frequencies) used to enable 5g. Additionally, 5g deployment is fairly variable by region and it may be that your region is one with sparse coverage. Additionally, your phone may intentionally switch off of 5g to save power.
Here's an example page.
https://www.kimovil.com/en/frequency-checker/US/google-pixel-6
Edit: if your phone is less than a couple years old it may be a warranty issue for the heat and battery. (unless you got malware or something drinking power.)