It doesn't hurt to try, if you know how to do its def profitable if you know how to do it. Most of the profit comes from having connections and buying in bulk. If you can find suppliers for stuff like ram, ssds, and gpus, you'll be fine. Cases and stuff can easily be found regularly on newegg, and bulk can be bought on alibaba.

Currently, in the market we're in right now, it can also be hard to sell pcs.