True, but those small beans can all add up. its my first build in 10 years so can afford a bit more but still want to stay within my budget and find a balance between getting what i want / need. ideally current prices would be sane in a ideal world and not insane like mobo's and GPU's are half my budget is taken up with the GPU its insane.
In your circumstance, I think the question I'd be asking (before spending the extra £100-£200 to have the M.2 slots) is: "will a PCI-E 5.0 drive offer my work apps a utility/performance benefit that has the potential to save me an upgrade?".
I would, for most systems, answer that question with no, since the degree that they're bottlenecked by storage is so small that it's very rarely worthwhile. It's also unlikely that PCI-E 5.0 drives will be fast enough, soon enough, that they'll be cursing their board for PCI-E 4.0.
With your circumstances, that might be different, since SSDs can have an impact on usability of the system, e.g. streaming assets, responsiveness of viewports, frequent loading of large apps/projects, transferring large volumes to backup drives or from scratch disks.
You could also make an argument that you'll keep the money now and just upgrade the board if PCI-E 5.0 is necessary later, since you should be able to use an old CPU in a newer AM5 board, but with a workstation that's going to be more time consuming and awkward than a gaming PC.
