I've read that some people have problems, but I used to dual boot (now I keep each os in a separate hard drive) without issues. Is a really straight forward process but if you get issues the online community is amazing and there are tons of docs (and reddit threads, some of them are deleted now or moved to Lemmy).
Linux is great! I started dual booting windows and Linux Mint, tried a lot of distros (this is called distro hopping) all Ubuntu based while using primarily Windows. After a while I got tired with windows and felt more comfortable with Linux, so I wiped Windows and installed Fedora Workstation (there's a community for ASUS gaming laptops that have a guide for Fedora).
If you just want to get a feel of Linux, you can also run it in a Virtual Box, setting it to full screen makes you feel like you are using Linux, but obviously that comes with limitations.
Is it possible but you could run into issues. You can shrink that drive and leave space for Linux there, but be careful while setting up your partitions so you don't accidentally erase your games data.
Its always easier to use a whole drive so you don't have to worry about partitions. I've never done what you're describing but it shouldn't be much of a hassle.