If the Dell is old enough, you can use a printer port for some GPIO. Pretty trivial to use.
Memories. A long time ago I used to sell a little board that plugged into a printer port and added a power driver to the outputs and some buffering to the inputs so they were 12V-tolerant.
Forgot about that until you mentioned it.
Hah, memories.
Wrote a Turbo Pascal program for that. Good times.
There are now cheap PCIe cards that provide 40-pin GPIO headers, check eBay. You might need an M.2 to PCIe riser if you don’t have a PCIe slot.
Even easier: there are direct USB-GPIO adapters.
I didn’t know that, thanks for the info. That’s a lot easier.