Yes ─ I’m sorry but I only just remembered that you may need to include zstd support when reinstalling GRUB for a btrfs-based system.
sudo grub-install --recheck --no-rs-codes --modules="btrfs zstd part_gpt part_msdos"
sudo update-grub
Also make sure that you add the btrfs and zstd module support in /etc/default/grub, for future reference.