Comment by vitorgrs
They are not blocking Cloudflare or Fastly.
They are blocking X IPs being used on Cloudflare and Fastly.
These CDNs agreed with Anatel, to reserve IPs exclusively to X, so IPs can block X without collateral damage, that's all.
That said, Cloudflare is also blocking X. Cloudflare Warp doesn't open X.com anymore, neither iCloud Relay's (which seems to use Cloudflare).