Extending grace period.

Aside from a clean reinstall, Timebombs are timebombs end of story.  However, even insider builds will allow you to put in a purchased Standard or Data Center key for Windows Server 2025 (even if it's not for ARM the key works the same).  To enter the key you would simply use the settings activation change key.  This will remove the timebomb and allow you to continue to use your already configured Windows Server 2025.  You should still be receiving Canary build updates through Windows Update also unless you opt out of the Insider program.  I've tested their OS's since 1996, Microsoft is never going to tell you how to bypass a timebomb.  And trust that the timebomb code is in multiple files of the build intentionally to prevent bypassing it.  So time to clean install, or shell out the dough for a license to Server 2025.  And the license is only good for 2025, not whenever vNext comes out.

how do i get the ISO file for this i also want to try? 

I used the command (as Administrator):

slmgr /rearm

and restarted the server.

After that moment, the following errors started:

Log: Application

Source:        Microsoft-Windows-Security-SPP

Event ID:      8198