Photon is available for any instance at https://phtn.app.
Alexandrite is available for any instance at https://alexandrite.app.
I don’t like when instances will host photon for anything other than the default interface, as then it’s just a more limited, outdated version of photon and another point of failure.
Photon technically has it but you need to use your own libretranslate instance since I’m not paying for that.