LG UltraFine 27MD5KL-B was designed for Mac, so you can expect it to work with all newer Macs. Windows, on the other hand, works with all monitors (as far as I know), so that shouldn't be a problem either. The sticking point is how to connect Mac and Windows. Do you want to change the video cable every time? Probably not... The monitor has only one Thunderbolt input and Thunderbolt KVM switches do not exist. Would a USB-C switch also do it, so that the functionality remains? That's a big question that may be at least partially answered in these two articles:
https://www.notebookcheck.com/Das-Apple-...
https://nielsleenheer.com/articles...
Otherwise, there is the option of controlling Windows from the Mac via Remote Desktop or setting up a virtual Windows on the Mac, in which case you don't need to switch monitors, mas, keyboards or anything else.

I use the monitor with a Lenovo notebook without any problems.

Yes, that actually works! I do the same with your Mac Studio and a Lenovo X1 notebook.

This should work without any problems.