So it seems you:
- fully cleaned up up the old setup
- actually read the INSTALL file
- installed haproxy cleanly
- setup systemd properly
Now you got a proper installation with the correct setup. Thumbs up from me. I’d say now you know more about setting up haproxy on linux than the average users here in this forum.
Just one thing I noticed: you should grab the latest 2.2.5 release as opposed to 2.2.2, so you have all the latest bugfixes. Upgrading should be a non-issue, a make install should overwrite the executable and with a subsequent reload you are done.