You can create up to twenty manual save games. Assassin's Creed Valhalla also creates save games automatically after key moments in the game and when performing some actions such as fast travelling on the map.
valhalla is really good with how you level up, and difficulty customization. The world is just as good in all 3 games in different ways. The loot can be kinda boring in this game though, just cuz if you want you could just stick with one set all game, as you do get one of the better sets early game.