i have configured nix.gc to delete all prior generation after upgrading.
$ ls /mnt/nix/var/nix/profiles/
per-user system system-134-link
$ ls /mnt/boot/loader/entries/
nixos-generation-108.conf.tmp nixos-generation-109.conf.tmp nixos-generation-110.conf.tmp nixos-generation-134.conf.tmp
Should i try bootctl install?