>>1935765You should be less concerned about width and more concerned about the low rolling resistance you get from an expensive tire that doesn't spec much into durability.
Most cheap Kenda CST etc or otherwise city/touring tires in the 1.5-1.75 'road slick' variant will still be significantly slower than a fancy fast 2" tire like a Racekang or Kojak.
A better hybrid tire like a Panaracer Pasela, the lighter Marathons like Almotion and Supreme, Conti Contact or Ride Tour, would be alright and reasonably reliable, although in the scheme of things for nice tires, quite heavy and sluggish, and not amazing grip. Look at the weights and try get a folding bead.
A dirt jump/ gravel tire like Billy Bonkers, Maxxis DTH, or Gravelking are reasonably fast. Those are probably the best allrounders. Though also, not 'fast'.
New higher-spec XC tires like Conti RaceKing or CrossKing are fast. Like, catagorically way better than the knobbies you're used to.
Fragile meme tires like Schwalbe Kojak or Rene Herse are likely to be the fastest, if not have the best ride quality.
You can also get outright road tires for 26" like Schwalbe make a number of high spec One tires, some aimed at wheelchair sports, and conti do 26" Grand Prix. At this point unless you have some good meme reasons though you'd be much better off with a road bike. You can ride a straight up road bike on the terrain that you're explaining, so a road tire would be perfectly fine, just a risk.
That's the thing, fast tires are fast. You want to be fast you need fast tires. They are expensive and they are somewhat fragile.
