After getting 4 flats in 4 days on a bike trip, I had good luck with anti-puncture kevlar tire liner tape.
The one time I had it fail me entirely, it was in New Mexico where the goathead thorns are relentless. I had about a dozen thorns in each tire, and my half dried up sealant was no longer up to the task. Still hard to imagine going back to tubes, even though I carry lightweight TPU tubes as backups.