It's been a little while since I've read through the entire manga but isn't the knowledge of Odic force pretty unknown? So is this Felix dude a mage? We've had them mentioned a couple of times but they're usually laughed off. Wonder if he knows about the existence of the death gods as well
Oof. Yeah, I can see how that might be an issue. You could try creating a tag category for the manga that haven't had an update in a couple of months and set the tracker to ignore the manga in that tag category. Then just manually update that tag category every couple of months or so for any updates. That should reduce the number of requests quite significantly, assuming you aren't also reading multiple 100s of manga actively right now.
Edit: Category instead of tag since that's what Tachiyomi calls it
How many manga are you following? At my peak, I had a little over 100 manga from mangadex and I was able to use Tachiyomi to track them without any issues.