I tried both with and without ventoy
I think I managed to sus it though. I think it's an issue with my GPT partition from when I cloned my old SSD.
I opened the terminal in the installer and when I tried to mount the NVMe it would return a warning saying it was read only..I suspected windows at first, but then I booted my Pop_OS installer and I noticed that their installer was picking my drive and it's partitions but gparted wasn't.
I then reformatted the drive again and remade the GPT partition and voila, the NVMe is showing now.
Worth noting that I also tested it with an external enclosure and it was giving the same issue, so to answer the question, yes it was plugged into my motherboard directly, but I had tried both ways just to be sure.
I went the lazy way originally, and cloned the old NVMe using diskgenius and I think it didn't do a good job. I've left clonezilla running overnight and will test it again later today, but I'm pretty confident it'll work now