Put a GParted ISO on a thumb drive using Rufus or BalenaEtcher, in your BIOs change the boot order so that GParted boots first, boot into GParted an then readjust/delete your partition as you need be.
Pretty straightforward for the most part.
Does your laptop have 2 GPU’s?
NVIDIA Optimus sucks for Linux, I would suggest looking into EnvyControl and forcing your xorg & xrandr to use your NVIDIA GPU primarily and not the iGPU.
The day I do the old fashioned sudo apt update && sudo apt upgrade and everything suddenly breaks is when I know I’m on Debian 13.
I honestly never tried Ventoy myself so I can’t really give you a proper answer to this however, after reading into it I see no reason why it wouldn’t work? So long as GParted can access the systems disks there shouldn’t be an issue.