I believe cloudflare only blocked archive.is on their "Families" filtered dns. I've been using their normal 1.1.1.1 and haven't encountered any blocks.
Yesterday 1.1.1.1 failed to resolved "theinformation.com" (hosted on CF itself!) for many hours, answering NXDOMAIN.
IIRC the block was on archive.today's side as a protest against 1.1.1.1 intentionally not supporting ECS.
https://news.ycombinator.com/item?id=36971650
https://news.ycombinator.com/item?id=19828702