Here are some things you can try:

- Cycle (power off and then on) all of your hardware. Your computer, your router, your modem, and any other networking accessories you might have like signal boosters or wi-fi meshes or any of that stuff.
- Try a different network for an evening. Most mobile devices that have 4g/5g can be used as mobile hotspots. Simply playing the game uses very little data, so no need to worry about that. If you don't experience any issues on the mobile network, it'll eliminate your computer and game installation as the culprit(s).
- Try using a VPN for an evening. Most VPNs have a 'free version' which will work fine for this test. Turn on the VPN, select somewhere moderately far from your home (live in western US, select central US, etc.) and play. If you don't experience any issues with the VPN, then there is a problem with the normal route your data is taking.

There are more detailed troubleshooting steps to find the issue, but they're more in-depth. If none of the above have any positive effect on your game play, you could start looking into running a WinMTR to see if packet loss or bad latency are occurring. Here's a thread that details that process very clearly:

https://forum.square-enix.com/ffxiv/...ns-included%29