I’d lean toward upgrading the headset first since VR clarity is more limited by display resolution than GPU at your level. Are you currently hitting performance limits in your main sims or mostly just noticing blur?
With your setup, Quest 3 PCVR should run fine, so hardware isn’t the main concern here. For your vision conditions, results vary a lot, so testing with a return option is the safest approach, have you tried any VR demo in-store before?