There's one group of Android users Google's new sideloading rules won't affect
(www.androidauthority.com)
Yes. Provided you find a phone that can unlock the bootloader and you are fine in losing banking app, government issued apps and such amenities....
Given that Samsung and Xiaomi doesn't let you unlock anymore.... Unless you are ok giving money to Google to buy a pixel, new or used, there are really little choices currently. Nothing phones, a few motorola (hit and miss...).
For example, we have digital ID that you can load on the phone your ID card and driving license, which is not allowed on unlocked phones. Also, McDonald app doesn't work on unlocked phones ...
So good luck hoping people will use custom Roms, even less than before. Google is fucking us a small step a time.