Manjaro, btrfs, root volume, not working

Two different pieces of advice (I have no experience with btrfs):

I can't run manjaro-chroot on vm with brtfs filesystem - #2 by brahma

says that manjaro-chroot can’t be used on btrfs
but rather the manual method as, for instance, described in the Arch Wiki.

chroot - ArchWiki

and then there is this:

Computer won't boot after Kernel update - #10 by stephane

mentions a different method.

I don’t know whether either one or which one is correct.

HTH nonetheless!