These will need a little personalizing as well, but since you do use restic, everything should be obvious. The backup alias first does a backup, then prunes the repository to leave only the most recent 5 backups. You're asked for a password for both operations (backup, prune), so if for some reason you don't want to prune the repo on that occasion, you can bail out of that part. I've tested this on 4 Plasma machines and 2 Budgies.
alias bkup='restic backup -e "/home/jerry/VirtualBox VMs" -e /home/jerry/.thunderbird -e /home/jerry/.cache /home/jerry -r /mnt/Backups/Linux/
alias pruneBkups='restic forget --keep-last 5 -r /mnt/Backups/Linux/
alias backup='bkup && pruneBkups'
If you want to keep just the last 2 or 3 backups, that should be plenty. Normally, if you need to restore a backup, it's one that you've saved recently. I save 5 for each machine, because these are going onto an NAS with many terabites of empty space. I figured, why not?
The exclusions ( -e ) are to avoid backing up huge amounts of data that don't need to be backed up. I don't back up my VMs, for example, because those are backed up by snapshots in the VBox manager. And I don't back up the email archives for Thunderbird, because my accounts are IMAP, so those are stored on the mail server.
You'll need to replace my repositories ( -r ) with yours, but you've certainly done that before. Everything else should be self-explanatory. Good luck with them.