Man, I totally get where you're coming from! Last year, I pulled a similar stunt with my old man – got him a shirt that said ""Dad Bod Loading"" (he's been talking about hitting the gym for ages). He chuckled, but I could tell he was hoping for something a bit more heartfelt.
This year, I decided to go all out. I remembered all those times we'd spent tinkering in the garage on his old Chevy, so I hunted down a vintage car manual for that exact model. When I gave it to him, his eyes lit up like a kid on Christmas morning. We spent the whole afternoon flipping through it, reminiscing about oil changes gone wrong and the time we accidentally painted the driveway instead of the car.
If you're looking for something that'll hit him right in the feels, maybe think about a shared experience you two have had. Could be anything from a framed photo of your first fishing trip to a playlist of all the dad-rock songs he subjected you to on road trips.
Oh, and if you're still stumped, I stumbled across this site called DadShop
link while I was brainstorming gift ideas. They've got some pretty cool stuff that goes beyond the typical ""World's Best Dad"" shtick. Might be worth a look!