Moodle 3.5.x automated backups in Moodle Admin, looks to be the same as in 3.4.x.
No finer controls to exclude certain courses by size of backup or by their ID numbers.
Same is true of CLI script for autobackups.
Ditto 3.6.x
So this issue, which is affecting more than one admin/site, hasn't reached threshold where it's revisited or improved in the Moodle Admin UI. Maybe some Moodle Association member will 'spend' their votes on addressing the issue.
Didn't find anything on any Moodle Roadmap for future versions of Moodle, but that is sooooo easy to miss ... not find.
Until then, looks like truncating that one table that tracks and then running and/or one's own bash shell scripts are the only solutions for sites afflicted.
We have off-loaded cron jobs now ... wonder if an off-loaded autobackup would work ... or how it would work .. to relieve strained Moodle servers. Just thinking out loud here! :|
'spirit of sharing', Ken