Try latex tubes. My bikes max out at 700x25, so my only option for softening the ride on our increasingly rough chipsealed roads was to try latex tubes. Really helped. I'm not strong enough to notice any difference in speed due to reduced rolling resistance. But it's more comfortable, which matters on longer rides.

If you go this route, check out the tutorial videos by Silca. Very important for properly installing latex tubes to minimize problems. Since the Silca video was done they've begun pre-powdering tubes to ease installation with reduced risk of pinch-cuts against the rims. But I add a little of my own corn starch powder for subsequent uses. And be sure the rim tape adequately supports the tube -- some folks recommend tubeless rim tape rather than cloth or others.

So far my only puncture with latex tubes was user error -- I neglected to follow the advice to use tubeless tape and just used the Velox cloth tape that was already on the rims. There was a tiny bit of something sharp embedded in the cloth tape that punctured the tube on the rim-facing side. I was able to patch it using Lezyne self-sticking patches, which are very unusual -- they're paper thin, very soft and flexible, and the adhesive seems to get stronger and bond more securely with age. I used a Lezyne patch to repair the puncture and left it for a few days before riding. No problems since.

However I would advise carrying one or two spare butyl tubes for use on the road. Patching a powdered latex tube during a ride is a PITA. Quicker and easier to use a butyl tube, then patch the latex tube later. I usually carry super light Continental Race 28 Light tubes on my road bike seat bags, since I can carry two in the same space as one regular butyl tube. The Conti Race 28 Light tubes have been more durable than I'd expected, despite being so thin.

Tubeless is another option but I haven't tried it yet.