The Garand (USA) outclasses them all. And also outclassed its SVT40 (Russian) and K/G43 (German) semi-auto rivals. Arguably the M1 Carbine (USA) may have been better still.
But if we’re sticking with bolts........ in combat I’d have to echo the prevailing majority and say the Enfield No. 4 (Great Britain) because it’s fast, has extra mag capacity, and also has aperture sights. The SMLE (No. 1 Mk III*) is basically the same gun only a slightly different look and has a conventional open sight. The French MAS36 probably comes in second (almost as fast, sights also aperture), but these didn’t see a lot of combat and couldn’t save the French army from being overwhelmed by tanks and superior generalship.
There’s precious little real world combat difference between a 7.7 Arisaka, a Mosin, a 1903, and a K98k.
The 6.5 Arisakas (Japan) have the advantages of the Mauser types with less recoil. The last ditch 7.7 type 99s are all good, solid guns. Maybe a bit ugly but still fine rifles in a fight.
The 03A3s (USA) have aperture sights which might put them slightly ahead of the others (but if you found yourself with one you’d curse it mightily because it means you could have had a Garand if you had the fortune to be in a different unit.)
The K98ks (Germany) kick hard, but not much harder than most of the other rifles, so this probably comes down to individual preference. They are robust and reliable with a satisfying action that encourages trust. They also have sights that are very precise but not the easiest to use in a hurry.
The Mosins (Russia) have the most variable quality control (a good one is a nice rifle, but one made in a hurry when the Germans were 30 miles from the capital can be ...underwhelming...) but probably the least satisfying action in terms of “feel.” They weren’t cheap to make or incredibly robust, just Russian: designed to pinch pennies at the outset in 1891. But they shoot, and are accurate (they’re sighted in for a fixed bayonet so if you don’t know this you might find yourself wondering why your rifle can’t hit the broad side of a barn.) I would not feel badly armed with one, unless I were facing enemies armed with Garands.
The Finnish Mosins are even more accurate, generally have better triggers and sometimes better magazines, and are not sighted in for a fixed bayonet. The M39 with its upgraded sights and semi-pistol grip stock makes for a very accurate rifle.
The Carcanos are not terrible rifles, but they’re crude feeling, and they rely on en-bloc clips which are hard to find nowadays, without which the rifle is useless. I’d say they’re my least favorite. They also get a bad rap because some of the surplus rifles commonly seen are actually Vetterli-Carcanos originally made for black powder, and were fitted with magazines and lined bores for the Carcano cartridge as a WWI emergency measure. These guns are known to blow up.