Very Slow boot time on Mint-19.3

Every boot I have to wait

1. 30 seconds while it scans for Btrfs filesystems, which I don't have. It scans anyhow.
2. 1 Minute 30 seconds (just after it sets up ntp) while it is reporting Code: a start job is running for dev-disk-by-2uuid <long string of gibberish>.device

I had a previous unsuccessful try on the btrfs thing. The irritating thing is it knows exactly that this job is going to take 1min 30s and it counts that, whereas no program ever knows how long it's going to run for.

The big thing going for systemd is not ease of configuration, elegance of software, but that it's fast. Mine sure isn't. I'd have updated this to Mint-20 except that enforces UEFI, which I have disabled. How do I get rid of those systemd jobs?