the newest. it doesnt say the version and i dont know where to check it. the oem version sucks, theres barely any settings. as soon as i set it up it automatically upgraded the oem firmware against my permission even though i disabled automatic updates.
Nothing to do on that front if latest. I guess you you could try master image, but it has been a long time since anything has come into the tree around flashing this device. Be sure of the image you are downloading, checksum verify the download.
Given that you're new to OpenWrt - if you rely on your wifi don't install the 21.02.1 build. Keep/update your OEM firmware until 21.02.2 comes out because it fixes a significant wifi bug, then install the factory version. If you want OpenWrt now then install a master build and install luci and everything else via SSH.