what parts of a loop can I save money on and what brands should I look at/avoid

feeling like its time to step up my game from an AIO but custom loops are expensive and intimidating, just want to know where I could be saving money and what companies I should be looking at or avoiding.

realistically, I don't need to squeeze every bit of cooling performance I can out of it its really just for my own satisfaction of having a custom loop

Also happy for links to good youtube vids/channels to help educate myself also