Hello, Tiggaknock.
Thank you for contributing to Apple Support Communities.
We understand that you’ve been experiencing some cursor and slow or unresponsive issues with your MacBook Air. While we haven’t had the specific issues ourselves, we did take a minute to do a little research for you.
It sounds like you’re experiencing it mostly when you’re trying to use Microsoft Remote Desktop, and when using your iPad with Sidecar.
We found this thread in the Microsoft forums referencing the issue you’re experiencing with lag in Microsoft Remote Desktop, and it appears they were able to narrow it down to the connection of a specific type of third-party mouse on their setup.
Extreme lag on Microsoft Remote Desktop Mac client - Microsoft Q&A
With this in mind, you might try a few different combinations of your setup to see if it looks like one of the accessories is impacting performance.
- Try without any peripherals connected, using the built-in screen and trackpad on your MacBook. Do you have lag here?
- If not, add one thing at a time to see if it returns. Start with your external monitor (or iPad).
- If the lag does’t return with the iPad connected, reconnect your external mouse (if applicable).
You get the idea. We’re curious about whether we can narrow it down to a compatibility or interference issue between the program, your MacBook Air, and a specific peripheral.
You may also want to reach out to Microsoft directly to see if they have any ideas: Receive Remote Assistance Support from Microsoft
Cheers.