This is probably not an issue on this mods end but I am cross-referencing this here as well for any additional information

Sinytra/Connector#1692

You cannot swim with Connector and Oxidized. You can only swim in the Y-axis by looking in the direction.

1. Install Connector and its requirements with NeoForge
2. Install Oxidized
3. Attempt to swim in any pool of water and notice you simply cannot for some reason

debug.log

Doesn't occur in a normal Fabric environment so there's a conflict with Connector itself here

A similar issue was reported here but I narrowed it down to connector: Sinytra/Connector#1502

https://www.curseforge.com/minecraft/mc-mods/sinytra-connector