Looks like it has an ARM CPU, a RK3588. Similar ballpark to a Pi 5 in CPU performance.
Installing another OS would be technically possible but not easy, you'd need a Linux kernel with the RK3588 drivers already in it. Then there are differences between it and other RK3588 SBCs that could cause problems.
Much like you wouldn't want to install anything other than raspbian on a Pi, you'd be best off with ugreen's OS even if others are technically possible.
This from the company that started the netbook trend with the $400 eeePC in 2007...