Multiplayer Server stability / connection issues

New server created in 1.19 RC2 then upgraded to 1.19

Locally connecting has no issues

Remote connecting seems to be hit or miss, more often miss. Can connect to server fine, but then cannot interact with anything and get 'timed out' after about 45 seconds. This can go on for multiple hours and then suddenly seem to work fine. Same server hosts a 1.19 RC2 and a 1.18.2 server without any issues (tested repeatedly).

 

Pure vanilla server, using MineOS on the server to manage. I'm running a pure vanilla client as well.