Recently, since the current Lemmy versions for this instance (0.19.0 for UI, 0.19.1-rc.1 for backend) may not be up-to-date with the final release of version 0.19.1, would an upgrade to the final version of 0.19.1 help with any issues the instance is suffering from lately?

I'm not sure if this will resolve the federation issues the instance is currently having, but hopefully this helps.