In that case, I suggest that you follow the previous suggestions, and run
restic forget --dry-run --keep-within 2m
2m refers to within 2 months of your most recent snapshot, and as @rawtaz mentioned, there are good reasons for using the time of most recent snapshot rather than the time at which you run
restic forget. The reason is that if there are no recent snapshots this ensures that you will never be able to delete all of your snapshots using this command.
If you run this immediately after doing a backup, however, this is pretty identical to removing all snapshots older than 2 months, because the most recent snapshot is only minutes old.
If you like the output of the above command, run it again without the
--dry-run parameter, to actually remove the snapshots from the repository.