I have a dual boot Linux/Windows
I switch OS every day, several times.

Windows is on an NVME (NTFS)
Linux on a sata SSD (ext4)
I also have a 10TB disk for my DATA in NTFS

I bought another 12TB disk (because it was 30% cheaper than the 10TO)
I would like to do a software RAID 1 under Linux on this hard drive, but for it to remain usable from Windows, and for the raid to be resynchronized automatically if necessary when comeback to Linux.

Several questions :
1- Top priority: build RAID 1 without messing up the data on my original data disk
2- Is it possible to make a 10 TB partition on my 12 TB disk for the raid and keep the remaining 2 TB for Timeshift (which does incremental backups of my Linux): timeshift backups do not need to be on a raid.
3- The crux of the matter: being able to access (read, write, delete and update) my DATA from Windows, and for raid 1 to be resynchronized when returning to Linux (just what has changed, if something has changed, it shouldn’t take hours)

Thanking you for reading and responding.