This.
The only reason it works for these standalone games is that once you die, you can just hop into a new match.
This doesn't happen on Blockland. Everyone's just going to get sick of waiting and you know people will stall it out on purpose.
Yeah, something with as huge of a scale as pubg simply isn't going to work for this reason.
But that doesn't mean something smaller scale and faster paced couldn't work.
I'm not sure how displaying the blue/white circles on a map could work in BL, so you might need a different concept.
What about 10-20 players thrown into a small village, with individual houses gradually being bombarded and completely destroyed?
Or you could go hunger games route instead of pubg, and instead of having a shrinking playzone, have things like hunger and natural hazards