There's multiple ways with multiple tools to transfer files between computers.
- Transfer cable
- External HDD
- Network connection
I would suggest since you've got a new PC, it is the perfect time to start looking into ways of working so you don't have to ever go through this again.
The way I do this is by backing up my projects to multiple external HDD destinations.
This is just an example that I use for this purpose, I'm sure others have methods that work for them as well.
My Laptop's internal drives are Drive-C and Drive-D. Drive-C is my OS drive, Drive-D is where all my projects that I'm currently working on reside. I don't put any media/projects on my C-Drive, although I could. They're both SSDs inside my laptop. What you will see is that I also have multiple other HDDs which I backup the projects which reside on my Drive-D. I backup the projects to my locally connected 5TB L-Drive, as well as my 4TB N-Drive which is a network drive. Thus, I always have 2 backup copies of all my projects which are not physically inside of my laptop.
For the network drives, many use NAS setups but I'm not that sophisticated. I just have a router, my Asus-AC3200 which has 2 USB ports on it which I connect (2) USB 4TB HDDs to it. I strictly use these drives for backup purposes. Just like I use my J,K, and L drives for backup purposes which are externally connect via USB to my laptop. In the event my internal C or D drives fail, or my computer fails, I still have access to all my media and projects. Every PC I connect to my Wifi router has access to the network drives and can transfer files to/from them.
Also along the Network options. You could also turn on Windows Network File sharing and select to share the drive you have all your media on from the old PC, then connect the new PC to your network at the same time and just copy files from the old PC to the new PC through the network connection. Those file transfer cables are pretty much a waste in my opinion.
So anyways, back to your question. "I also have accumulated a ton of projects and wav files in that time as well. I would like to transfer some projects and their files over but not all. How do I accomplish this task?"
How would I accomplish that task? I would just plug my L-Drive into my new PC and then just copy over what I wanted to my D-Drive. I also have the option to copy from my N-Network Drive to my new PC's drive over the network connection or physically unplug my Network drive from my router and plug it into my new PC.
Now the tool to manage and sync these backups? There are quite a few out there. I use FreeFileSync. It's a folder sync utility which allows me to sync a paired set of folders and also supports network folder syncing.
https://freefilesync.org/