I have the same issue with DSA build in my R7800. I currently do not have Serial cable to get boot logs to debug the issue. We are discussing this in [PR] ipq806x: kernel 5.10 bump code propose. If you are able to obtain boot logs while and after flashing the DSA build, that would be helpful for the developer @Ansuel.
I flashed back to 21.02-SNAPSHOT using TFTP recovery method in my R7800, which is working. I am also not a developer to be able to propose any changes to fix this issue myself.