He also wasn’t asking for opinions on opinions but here we are.

Have you exposed your NAS to the internet so that anyone can reach it? If so then that’s the answer.

Or are you trying the VPN on the same network as your NAS is so when you disconnect from VPN you can still access NAS locally?

In short, if you disconnect from VPN and you are not on the same local network and your NAS is not accessible from anywhere then no you will not be able to access it.

There’s too many unknowns here to give a definitive answer.