What you're describing is the QA's role, which is absolutely necessary to do beforehand, so the devs can fix the crashes, freezes, or game-breaking bugs that could compromise play test sessions, preventing players from testing the actual game!

I disagree. Play tests should be about seeing how the players engage with the game: are the core mechanics and gameplay loop well understood, are the objectives clear, what strategies emerge, is the balancing right, where are the difficulty spikes, is the UI helping and relevant, etc.