I used to get this with Tumbleweed by the time I’ve finished my previous update.

I jest of course but I once had to update it after being away for a week and it had like 14 GB of updates. By the time it finished another 450 MB of updates were available.

Net update size: -50MB
Try using LyX on Tumbleweed. 5000 packages is not unusual
Try Slowroll for that kinda stuff. Updates just massively roll in in waves, and numbers above 4000 are not unusual