I've made YBCO superconductors in my garage many times and the solid state synthesis method in the paper is very similar to that used by hobbyists. In fact, it seems to not require the usual careful slow annealing under flowing oxygen.

I wouldn't be at all surprised if even simpler methods are feasible.

For instance, there's a rapid synthesis method for YBCO that uses a small alumina boat, some glass wool, a residential 800w microwave oven, and slightly modified mixture of precursors to allow free oxygen to be liberated in the mixture during heating and trapped in the wool around the sample so you don't need to rig an oxygen concentrator up. IIRC it only takes about 15 minutes to prepare a sample.

This is extremely exciting! I've read hundreds of papers on superconductor manufacture and testing over the years and this has all the hallmarks of legitimacy, at least from my citizen-mad-scientist perspective.