Even though I can't wait for this to be released, I won't play the beta either, same as I haven't played any BG3, so that I can experience it as fresh as possible when it releases. I did poke around for a bit in the alpha build they gave some keys for a few months ago. In that one, you were given a premade high-level party, so it was confusing to have a ton of skills that you didn't naturally learn and develop on your own, so I didn't care for the combat, but I liked the rest. To me, WH40k is not about the combat anyway, they could have made it a graphic novel for all I care. They seem to have improved a lot of things in the last few months, which bodes well - The UI looks already much cleaner now than it did back then, for example.
Hopefully, it will release near the end of the year so it doesn't conflict with BG3 because that's probably the only thing that can keep me from playing this on release.