Help! My usually well behaved cat has started to pee outside of his litter box
I have an adult male cat (exact age unknown) who's lived with me for over 3 years and has started peeing outside the box and the frequency seems to have increased over time. I've been trying to narrow down the reason, but I'm running out of ideas about what's wrong and how I could help and eliminate the problem. I do want to clarify that I'm not asking for medical advice and we do plan to take him to the vet soon but I want to explore whether or not there's something in his behavior that's fixable that I've missed, especially if it's a simple blunder so that I can save transportation and vet costs.
Some things I've tried based on past issues:
He is picky about his litter and when I was new I bought scented cat litter which he at first tolerated and eventually started to hate and started peeing outside the box. This was easily fixed with unscented litter.
I was very sick once and didn't scoop his litter on time. Pee outside the box again. Fixed getting help by cleaning the box on time. Problem solved.
Now my problem is that he for whatever reason just doesn't want to pee in the box at all. His litter is unscented and the box is very clean as well. He only poops in the litter box. I noticed that he appears to hold his bladder just to avoid his box altogether and will pace around the house and yowl until he can't hold it in anymore and leave the biggest puddle known to man right on the tile floor. I thought it was the new furniture, so I asked my family members to slow down with all that they're buying but it hasn't helped at all.
I've resorted to closing the door to the room which has his litter box with him in it when I see him pacing around to pee outside again, and only then does he pee in the box. But I have noticed that in doing that, he'll hold his bladder and patiently wait for me to open the door so that he can pee somewhere outside the box!
What is going on??? Please help me!!
Possibly relevant health info: has good appetite, drinks enough water, a bit grumpy maybe because of the peeing issue (?), healthy stable weight
EDIT: for clarity