"I can ssh into the server without issue from Termux on my phone" – (1) Do these successful tries also use
root as the username? (2) In these tries, does the server also gives you its identity as SHA256:cVWa/71WRIborznzgOMV900LrGYK0fxXUjFi9N6ESsM? My point is maybe some (yet to be found) quirk makes you connect to two different servers.