Are you aware @Ray-Ven that we are constrained from answering you due to
I suggest you avoid switching back and forth to Testing in Developer options at this stage but take advantage of the help you are getting from the testing team in your Gitlab issue #8113 and perhaps join the testing team.
Btw sideload won’t work with the “normal” /e/OS fp4 ROMs with a prefix “IMG”, these are installed like this.