I mean, you can reward XP for anything. There is nothing stopping you from rewarding it for downtime activities. They're spending resources, accepting opportunity costs, and taking the risk of complications.
Meanwhile, there are pretty notable training costs in the downtime rules.
In my group, we often tend to forget to reward much money, so we have no trouble finding things to spend it on, but in a "normal" game, there are ships, hirelings (who can be set to do downtime stuff for you while you're adventuring), crafting of consumable resources (poisons are pretty potent, and pretty fairly costed compared to learning ritual spells, I've found. Two hours to learn to make it per 50g of listed cost, and you have to spend the full cost as part of learning it.) I just wish alchemical items had as many examples and as solid a pricing scheme.
One thing I have seen help a lot is to simply work out a more transparent scheme for crafting magic items, put a markup for commisions, and run a game where all the good magic items weren't crafted thousands of years ago, but are being invented now. Doesn't work for everyone, though.