I get this problem with family too - the person who seems to have everything already has it, so you end up staring at gift guides feeling stuck. The best approach is shifting away from objects entirely. Experiences tend to land way better: tickets to something he'd actually go to (concert, sports event, restaurant he's been wanting to try), a weekend trip somewhere, or even just booking an activity you two could do together. If he's into anything specific - golf, cooking, travel - you can go deeper into that interest without buying clutter. A nice bottle of something he likes, a membership to a club or service he'd use, or even just cash with a note saying "let's grab dinner on me" can feel more thoughtful than a random gadget.
If you want to go the stuff route but keep it minimal, think consumables or upgrades to things he already owns. Quality bedding, a really good robe, premium coffee or tea if he drinks it, a subscription service (streaming, audiobooks, that kind of thing). Or go the sentimental angle - a nice photo book, something custom made, or experience-based gifts like a cooking class or whatever his hobby is. The key is that it either gets used up, gets used a lot, or means something beyond just sitting on a shelf. Ask him casually what he's been wanting to do lately rather than what he wants to buy - that usually gets you somewhere useful.