There's a YouTuber I really like (I can't remember their name rn ;-;) who plays a lot of indie games. His general rule of thumb seems to be "play the first half of the game, let viewers get a taste of what they can expect from it, but don't reveal any spoilers". Ngl, I have looked into some games he's played simply because I was engaged with the story and wanted to know more.
I feel full play throughs should be done only for major games that are already really popular(Undertale, Skyrim, etc.) but not everyone has the chance to buy but they still wants to be a part of the phenomenon.