Test system

Macbook Air M3

Xcode

Xcode 26 is arbitrarily blocked from running.
At the same time new Xcode 27 beta arbitrarily blocks compiling of projects with my usual deployment targets, so I can't even debug my projects unmodified.
If these restrictions aren't lifted in the final version, I won't be able to install macOS 27 on primary development system, as I still compile programs for macOS 11 & iOS 12.

Networking

Various local network access features seem unusable, as if various apps were blocked from talking to local network IPs, but without any prompt or warning.
I had to use phone wifi hotspot + VPN to git push to a server standing next to me, as my git client claimed no route to host (even though I could ping & SSH just fine).

The dock

Hiding the dock is bugged once again, full screen apps randomly have their bottom parts covered by the dock that doesn't want to disappear.

Verdict

I have to disagree with popular claims that this new macOS update is more solid than the usual, it has repeatedly disrupted my workflow with obvious bugs within less than 24 hours from installing.