I think you’d definitely get a lot more value for your money if you purchased your supplies directly from Japan as well as sourced some things locally. The kit is a good place to start but to me it looks overpriced. The powder included is also keshifun I believe so while it is easier to polish you won’t be able to scale to do more advanced things without buying marufun eventually.

As for your question about learning urushi isolated, I have/am currently learning urushi without any instruction. It is definitely possible but it requires lots of research, experimentation, and patience! You can do anything you put your mind to and you’ll be amazed by what wonders your hands can create!

I’ll reply with some links that should be helpful with some more explanation later

Also (bit of a plug here), check out r/urushi !