Honestly a crappy situation. In Germany, Telekom is a monopolistic bully. In evening hours, any service behind Cloudflare more or less stops working (for instance, before I cancelled my subscription, chess.com web assets were delivered with neck-breaking 5kB/s, which made loading a 20MB wasm for stockfish analysis no fun).. but there are absolutely no viable alternatives that aren’t also crappy: Vodafone -> same peering idiocy, Starlink -> king Elon). VPNs make things complicated, but are often the only alternative.

I am on o2 and didn't have any problems with availability that I would notice.