@jon@henshaw.social No—only do this for platforms which are actually federated. Continue to use the platform's name and the non-federated username for monocentralized platforms (e.g. “@elon on Twitter”). This includes Facebook Threads, which has an end goal of being monocentralized.
Monocentralized services do not have federation-parts, and frequently they do not have open protocols either. Treating them the same way gives the illusion that there is some choice or freedom, which is not true. Do not do this.