You can't remove it, but you can hide it in a folder for unused apps, and not use it. You can disable it, by going to the wear app/watch settings/apps, scrolling to Google Digital Assistant and unchecking the "enable" box. If you are having issues with it, but want to use it, I would suggest force stopping it, disabling it, rebooting the watch and then re-enabling it. On the Watch Gemini is integrated with the digital assistant, while on the phone you can choose either/or. It shouldn't cause lag, though. Have you cleared the watch's cache partition? Issues with Gemini/Google Assistant would fall squarely in Google's wheelhouse.
