When I do long XC training loops (5hours) I use 2 x 750 bottles on the bike (king cages - really good) and stash a refill halfway. I carry a pair of tubes, a multi tool, lever, quicklink, patches and glue (no way am I going to gamble on only getting 2 punctures and being able to clear my tubeless set up of all old thorns etc) and a phone in a pack under the saddle. On me is 3 pockets of food with enough space to ditch the arm warmers if required.
The king cage allows you to take much bigger bottles. When I do the ridgeway double I'll be taking a standard 750ml bottle to drink from and a 1.5l to top up with.
I hate the noise, sweat and shoulder ache of camelbacks for longer distance.