Looking for insights: Senior male no longer giving signs he needs to go outside

My senior dalmatian (11.5) has started having accidents in the house lately. He's oddly just showing no signs of needing to go out lately, and just instead going inside. We let him out regularly with our younger dog and don't only rely on him alerting us by any means, but usually he'd be doing spins and giving *big signs* that he needs to go.

We've done several urine tests with the vet and he does not have any bladder or kidney infections, and has also tested negative for diabetes and cushing's disease. He is not drinking an abnormal amount of water, and his only poop accidents have happened while he's asleep...he's literally shit his bed. Thankfully they were solid and easy to clean!

We're waiting for the vet to give us suggestions on where to go next to try and figure out what's going on, and they also don't seem to think it's just incontinence from getting older.

Other new oddities: he seems hungrier than usual (no change in food; no drastic weight gain/loss), he has also pooped on the porch seemingly too eager for breakfast to even go poop first, and that's about it. Everything else seems like his normal self.

Any advice? Anyone experience something similar? Anything would be helpful because as of right now we are just in a waiting game with no real direction to go next.