@Greg_E Thanks for the update Greg! OK will keep going on mine. I had found some issues with one of the file servers which the testing was using so that could have caused my speed issues. I reckon I'll do domain/forest later on too but bring in user facing 2025 desktops first. I'm getting rid of folder redirection with One Drive known folders in its place then will be able to investigate Intune after that for round 2 of desktop updates! Good luck on your end.

@Greg_E Interesting to read through when having performance issues on my end too albeit not running ADDS on windows server 2025. Did you decide to upgrade your production system?
I'm building a new Citrix multi session image but have found many things "not responding" e.g. file explorer slowness and just opening task manager. I could be having different issues to you all and would need to provide more detailed info but working through the forums here and on Microsoft end to see what I can find against this OS and how the rollout is going. Any feedback on Windows Server 2025 would be great here unless we have another more suitable thread to follow.
Thanks.