Question for women who used to prefer receiving oral over PIV. And now they prefer PIV over receiving oral by alot

GF is like this. At first she preferred receiving oral because PIV caused her pain. Now she says she has no interest in receiving oral and prefers PIV. Alot of times when my body is tired or sore I don't really feel like doing PIV, just makes me more sore. It's easier for me to jerk off later on my own with vaseline to climax, like I can relax my whole body and I won't get tired or sore. I find it difficult to climax with PIV even with the lambskin condoms. Idk, PIV feels like --- slippery/smooth/feels like my arm muscles (triceps) get tired and I just never climax even after going really fast (which she doesn't like anyway, she just like very slow/shallow PIV + nipple suck for long periods of time). I like PIV but not for that long because I get tired/triceps get sore. I can't go in that deep without hurting her (dick is not that big, its only like 4-5 inch) so mostly its these shallow controlled thrusts that don't get me closer to climax. Occasionally she can take it deeper.

I am just trying to understand her head space deeply/like really understand and figure out what I should do. Idk whenever she does receive oral she seems like it, in spite of her words. So .. idk? Can I just ignore what she said about preferring PIV and just do oral on her and then chill out next to her? She pressures me to climax with her but with a small number of exceptions, I can't seem to do it. I had this problem with other girls before her, sometimes I just have to close my eyes, get the vaseline, and jerk off for like 20 minutes until it finally comes out.

Current plan is to work on my cardio: (swimming, seated bicycle, etc) + 1 week no ejaculation breaks to see if that helps