If it were true that it is impossible for the server providers working together to deanonymize someone, there would be no need for two different server providers at all. Apple could simply run two different servers on their own and say the protocol between them protects users (which isn’t true).
So has INVISV. update: Remove mention of specific MPRs by jonaharagon · Pull Request #2981 · privacyguides/privacyguides.org · GitHub
As far as I know this has never actually been tested, so you can’t say this with confidence. Warrant canaries are an attempt to defend against secret mandates, and such attempts are still worthwhile until it is proven that they are ineffective.
All of this ignores the fact that recommending VPN providers in the face of potential secret government mandates still would not be misleading, because we don’t claim VPNs protect against government surveillance like this in the first place.