I don’t think I’ve used any more than an i3’s worth of PCIe recently even on workstation builds. Only thing is in servers with lots of DAS enterprise SSDs which is a notable and large exception to what a workstation usually consists of as they usually cost house sized amounts of money.
It does not take much to exceed commonly available PCIe expansion. Most motherboards now will not support more than 2 big expansion cards and many are now down to only 1, which makes for a problem if you plan for a RAID HBA, fast networking, and the GPU. Back when I built my Phenom II system, even the lowest cost motherboards supported 3 big PCIe cards at a minimum.
I thought I might get around it this time with one of the Pro series of Ryzen APUs so no GPU is required however they are only available through the Chinese grey market.
What I ended up doing is finding one of the increasingly rare motherboards which support PCIe splitting. Had I not, then I would have had to move up to Threadripper at considerably higher cost.
If you need processing it’s waaaay cheaper to rent it from Amazon if you can as you’re paying by the minute.
My main workstation is a 16gb laptop. Anything that doesn’t fit gets sent to Amazon.
Even if I trusted Amazon, my available internet bandwidth and transfer caps make a remote solution untenable.
A monitor arm is absolutely fantastic to help reclaim valuable bench space. I used to scoff at the idea of spending say $100 on an arm but it makes a huge difference being able to reposition the monitor if you're working on something huge. You can often find a VESA mount as well for the ultra small PC's.
I like putting my mediocre woodworking skills to use to make monitor shelves restoring the desk area they would otherwise take.
Great thing about those tiny PC's is the low idle power usage, usually in the 8-12W range, so you don't feel that guilty for leaving them on while collecting data or controlling instruments. I do have a load of Z820 workstations and the ~70W idle is just so wasteful.
There are a lot of things to recommend small form factor PCs.
USB hubs still exist if there aren’t enough holes.
I would recommend using a USB hub whether needed or not. It might save the computer from an accident and it will certainly save the port on the computer from wear and tear. They can also be had supporting the higher power charging modes where computer ports do not.