I didn’t consider encryption because it wasn’t mentioned in OP and I have never used encryption
All I can find from searching this forum is how to use a mount partitions manually and chroot
Reinstall grub + BIOS + fully encrypted LUKS partitions, will this work? - #22 by stephane
But this post from the archived forum suggests manjaro-chroot should also work as
https://archived.forum.manjaro.org/t/how-to-chroot-into-an-encrypted-root-partition/10760
A viable alternative to manually mounting and chrooting