Cat having issues hitting litterbox

So I want to start by saying that he isn’t peeing in the middle of the floor or a different room, it’s completely him thinking he’s far enough into the litterbox and just letting it rip. 95% of the time he’s correct and he is in all the way.

My current setup is a litterbox inside a litterbox hide. A setup I’ve had for a few years now as I’m in a small apartment and wanted to hide it as it has to be in the living room. For a couple years he’d sometimes miss the litterbox by literally a quarter inch and pee between the litterbox and the door of the hide. I started putting pee pads under the litterbox to make cleanup easier. He could go months hitting the litterbox each time. Then there’d be a random apocalyptic week where he’d miss it a few times then just go back to always hitting it for months.

After the last time I decided to add a pee ramp. A piece of flimsy plastic that goes from the door of the hide and into the litterbox box. Thought the problem was solved.

Now it’s become an issue where he’ll miss the hide itself by a quarter inch. Something that went from happening a couple times a year where he’d just miss the hide completely to now once every week or two.

I scoop out the litterbox every other day and do a full clean once a week. The cat is pushing 20 so maybe is an old cat thing. I have taken him to the vet previously about it but there were no issues. He’s on wet food and has a cat fountain so his bladder and urinary tract is actually quite healthy from his last vet visit.

Really I’m just wondering if there are solutions to help make sure his accuracy goes up. Unless he is being spiteful because he only started missing the hide a few weeks after the introduction of the pee ramp. So totally possible he hates me.