Hey Michael,
Adding my 5 cents to all of the other great advice that you’ve already got.
When editing 4K on my HP Laptop (ZBook Pro, i9, 64GB Ram, NVidia Quatro RTX 3000, 1 x 500GB C SSD for boot & 1 x 2TB SSD for media). It works fine without going to proxy.
However, I run my Adobe project of the main drive, and all media of the secondary drive, or external SSD (tend to favour Samsung T7 @ up to 1050Mbps, USB-3 on a USB-C/Thunderbolt connector).
If it is a large scale project, I would recommend external raid or similar.
I still use the old adage of keeping at least 25% of free space on my drives for faster read/write.
On very large projects, even in HD, I save a new project version, and delete old time-lines from that just to keep the file-size down on the project itself.
You might also find it helpful to delete all of your rendered files, just to clear out the system.
WARNING: If in proxy editing mode, be careful that you do NOT delete the proxies.
Hope that this helps – Good Luck
Atb
Mads