Start with your basics, like you are saying. Pull plugs and number them and post pics. When ALL plugs are out, do a compression test. Maybe even a cylinder leak down test if results warrant it. Do you have a bore scope? Look for leaks, too.
I would suggest a cheap Amazon catch can. https://www.amazon.com/EVIL-ENERGY-Universal-Reservoir-Aluminum/dp/B081N392BNSo before I start any of that. I think my problem might be the PCV valve, or lack of. When putting on the intake manifold fold and the new valve covers i didn't think to put one on. I connected straight from the valve cover nipple to the intake manifold. Reading up on it, it seems to fit my issues. Will report back once I've installed an inline PCV.
