Provided the kernsize is correctly set, you have to ignore the LuCI warning when installing 23.05 factory.bin (or sysupgrade.bin) from an earlier version. Just Force an upgrade and do not keep settings. I don't believe sysupgrade checks kernsize imho.
The device page for EA8300 advocates use of factory.bin although sysupgrade is very likely to work too....
Did you see the link in the EA8300 device page regarding confusion whether to use 23.05 factory.bin or sysupgrade.bin.
https://forum.openwrt.org/t/linksys-ea8300-upgrade-to-23-xx/186462
In unlikely event you soft brick the EA8300, you should be able use the Recovery (Automatic) method to return to your installed 22.03.x