I’m not FiveM, and this isn’t customer support. This is you getting a response from a stranger on a community forum.
The warning in your first screenshot means the server is running an old version of FXServer.
The error in your second screenshot appears to make references to entity networking.
Older versions of FXServer (and thus older versions of OneSync) were known to have networking issues.
Thus it is likely the error is related to the server running an older artifact version, as opposed to something related to your client specifically.
If you would like any further help, I highly suggest filling out the entire Support Template, and taking the attitude down a notch.