Ever since I took the driver's theory test in 2019, I have thought it would be nice to have a free alternative to Official DTT Online. Since then, I've seen closed-source solutions like theory-tester.com and cheaper paid options like theorytestireland.org from third parties.
I've put up Open MCQ as a free self-hosted alternative. I've included a demo of the app, however, the 2019 questions may be outdated for current tests. Its self-hosted nature means you can customise it with your questions for your specific study needs.
It's going to be like the steam deck, I've yet to find a old Non-steam game that I couldn't run on the steam deck.