If you don't want to disassemble more, the only solution is to try unlocking it or cleaning it (with contact spray) by top like I explain here : https://video.latavernedejohnjohn.fr/videos/watch/44346503-e4e8-427e-bece-0b6750bf7336
But with the risk to ruin the OPU which do not like liquids inside obviously if you don't protect it and do a bad job.