How to rollback a btrfs snapshot for root [ / ] after failed system update

I tried updating from 18.04 to 20.04 but something went wrong and the installer told me that my system could have ended up unusable. I think I know the cause (a bunch of third party repos).

Fortunately I have snapper configured to make snapshots for @ and @home so I can just rollback / and try again; but how do I do this, will I need to boot to an Ubuntu's live USB and what commands shall I type?

I can still use my system, but I don't know what will still work once I reboot.

(already downloaded and burned using Etcher to an USB the Ubuntu 20.04 image just in case)

This is a sample list of my current snapshots:

ID 44624 gen 3718354 top level 9006 path .snapshots/88/snapshot
ID 44625 gen 3718355 top level 9007 path @home/.snapshots/88/snapshot
ID 44864 gen 3732417 top level 9006 path .snapshots/93/snapshot
ID 44865 gen 3732418 top level 9007 path @home/.snapshots/93/snapshot
ID 44912 gen 3735056 top level 9006 path .snapshots/94/snapshot
ID 44913 gen 3735057 top level 9007 path @home/.snapshots/94/snapshot