@Miraglyth Thank you very much for clarification, I've linked all platforms for safety purpose back in April 2021 when I started playing (after reading that PSO2 can mess files up and players were forced to download and re-install game) so it should be good like you wrote.
After doing further research, I logged into Xbox website and checked my Xbox Profile. I stumbled upon Achievements section and New Genesis CBT field was shown there but without any entries. I assume that either MS Store, SEGA or both parties were culprits that the results of our achievements reset somehow after Closed Beta ended and client was deleted / taken off of MS Store. I don't remember if achievements system worked during CBT but the results aren't saved for me on the Xbox website, it would be great if @Aldorik checked it out and let us know if there's something else instead 0/0. Also any info about CBT achievements is displayed only there, no other platforms (Xbox Console Companion, Xbox application) seem to show any stats about NGS from CBT period.
Another question, if I may...
Is there a possibility that CBT rewards are still being distributed and didn't reach players' accounts yet? Their way of explaining "Receipt period > Until 08/20 09:00 AM (Europe/Warsaw)" isn't 100% clear to me and maybe SEGA is still sending their rewards to all CBT participants by their ID numbers, that would possibly explain why I didn't get anything yet since my account was only 4 months old (maybe they're delivered in a timely manner from oldest accounts to the newest ones).
Nevertheless we'll wait and see how this issue is going to be addressed, it's on SEGA's side now.