People don't usually understand that apt allows you to configure multiple sources across versions simultaneously, so you can e.g. run stable, but also selectively install from backports or unstable.

To do so, add the sources for trixie-backports and unstable, and add the following configuration (e.g. /etc/apt/preferences.d/trixie-sid-pin) so that the system knows which sources your prefer:

   # Default to trixie
   Package: *
   Pin: release n=trixie
   Pin-Priority: 990
   
   # Very low priority for sid
   Package: *
   Pin: release n=unstable
   Pin-Priority: 100
   
   # Give backports medium priority
   Package: *
   Pin: release n=trixie-backports
   Pin-Priority: 500

   # apt policy linux-image-amd64
   linux-image-amd64:
     Installed: 7.0.12-1
     Candidate: 7.0.12-2
     Version table:
        7.0.12-2 500
           500 http://deb.debian.org/debian unstable/main amd64 Packages
    *** 7.0.12-1 100
           100 /var/lib/dpkg/status
        7.0.10-1~bpo13+1 500
           500 http://deb.debian.org/debian trixie-backports/main amd64 Packages
        6.12.90-2 500
           500 http://security.debian.org/debian-security trixie-security/main amd64 Packages
        6.12.86-1 990
           990 http://deb.debian.org/debian trixie/main amd64 Packages

> People don't usually understand that apt allows you to configure multiple sources across versions simultaneously, so you can e.g. run stable, but also selectively install from backports or unstable.

Which is just as well, because that's not generally a good idea unless you really know what you're doing:

https://wiki.debian.org/DontBreakDebian#Don.27t_make_a_Frank...

Granted, the kernel is probably the best thing to do it with, on account of their aggressive stance on compatibility and the narrowness of impact (no .so files in play).