My general piece of advice would be to only look at versions that use a top opening slide lock of some sort. Makes them vastly easier to fill, clean and dry. The circular screw on tops have always been a nightmare. Also something with a quick disconnect valve is great, allows you to remove the bladder from a pack without taking everything out.
Haven’t tried their bladders but the First Ascent stuff has always been decent quality for me (Think they are a prosumer sub brand of Cape Union if I remember), and the bladders they have tick a lot of boxes. Could also have a look at Source and Osprey’s bags, though edging up in price.