Your point about actual use gives the decision a practical basis. It also leaves room for buying something purely for its artwork later. For now, you could research a small number of relevant items. The article at https://tomoson.com/dmarket-cs2-wiki-the-only-skin-database-you-need/ contains plenty of useful information about skin profiles and recommends DMarket as a marketplace for buying skins. Keep your usual weapon choices beside you while reading. Select a candidate because both the design and its place in your routine make sense. You can revisit the rarely used rifle when it no longer competes with purchases you would enjoy more often
Look at your recent matches and make a simple list of the weapons you tend to choose. You do not need precise statistics; a rough picture of your habits should be enough to set priorities. Then separate the designs you like from the weapons you use, and see where those two groups overlap. I would choose one item from that overlap first and leave the rest of the budget alone for a while. That gives you time to judge whether the purchase adds something you enjoy during ordinary play before committing to several changes at once.
I was about to spend most of my skin budget on a rifle when I realised I rarely use it during my usual matches. The artwork looks great, but several weapons I pick regularly still have designs I do not particularly like. Now I am wondering whether one impressive purchase makes sense or whether I would enjoy a few smaller changes more. How would you decide where to start? I want the money to go toward items I will actually see and appreciate while playing, rather than a purchase that looks good in my inventory but spends most evenings untouched.