Windows decided to completely hide my other OS with a stupid update.

The update probably messed up the bootloader. If the Linux partition contains important and valuable works, then it is worth to revert the changes by recovering the Windows into its earlier state (before the update), instead of deleting everything. Windows makes occasional backups, so it is possible to undo the changes. And as I know, you can also edit the bootloader, and you can also access your Linux files from a live Linux system without editing anything. But I am not experienced in this part. Probably it is worth to ask the help of an expert, or at least the help of a more experienced user.

Good luck and all the best.