I did something similar to my own house several year ago- without buying a product like this. I had existing Cat5 cable that was originally installed for phone service.

We did this in about 92 with regular phone (cat3) wiring to get a link into a back bedroom. It was clean, but not fast by today’s standards. Fast for back then, though. The only thing we needed to wire was some rj11-to-rj45 connectors with corrected pins, and a two-port wall jack rewired for the crossover at the demarcation.