“Public domain” is a copyright term which isn’t really relevant here. The point the other user is trying to make is that, legally speaking, calling something “private” when it very well may be not private is at best disingenuous and at worst a lawsuit waiting to happen.
Have you tried the 64-bit(arm64) Raspberry Pi OS? The Pi can’t run 64-bit apps on a 32-bit OS, but the CPU is capable.