No. of Recommendations: 1
The thin clients are interesting, but I was thinking either very low-power (e.g.: RPi 2020 or RPi-Zero-2W), or going for the NUC mini-PC's.
I can tell you that a PI-zero-anything is not going to be powerful enough. Works fine for a pihole, but that's about it. A PI that is powerful enough and with enough RAM & storage is going to cost more than a used thin client. A well-configured PI is much more of a DIY project than a HP T620.
One of the mini-PC's would work, albeit 3X-4X more expensive. It'll probably have a more powerful CPU, but you don't really need all that much power. Many of these would be cheaper than a comparable PI.
I started off with a Pogoplug E02 ($10) as proof-of-concept and then upgraded to a T620 ($35). Start off cheap, upgrade when/if necessary, not much loss if you decide to ditch it.
I would probably do this in Python and have a cron job running periodically.
That would work. Have also seen people using R for financial screening stuff.
I have been banging bash & C for several decades and stuck with what I was conversant with.