Here is the most similar thread I can think of off the top of my head: looking at OPR across events
It’s more general than very technical though. My personal take on strength of field effects on OPR is that it is extremely game dependent. In some years, robot A competing at a weaker event will have a higher OPR than the same robot A competing at a stronger event, while in other years the opposite will be true.
The best thing you can probably do would be to pull out the components of OPR that are largely event-strength independent and then add an event adjustment to the other component OPRs based on the strength of their previous event. Now the exact components to do this for will vary based on the game, using 2020 as an example I would say you could comfortably pull out auto scores as being event independent, and then put an event-strength adjustment on teleop/endgame scores (do whatever you want with penalties, they are basically noise anyway). You could calculate such an event adjustment by comparing pre-event predicted component OPRs to actual post-event component OPRs to see if stronger events tend to have higher actual component OPRs than predicted.
This is all hypothetical, I’ve never done this kind of correction before but I think it at least has some sound theory behind it.
I’d encourage you to enter into my prediction contests whenever events start up again. Your predictions as they currently stand would be a very strong contender. They sound a bit too good to be true to me (or they come from very small sample sizes) but I’d love to be proven wrong.