I recently finished building my PC. Didn't really notice a big difference in performance from from my 5 year old PC though I maxed things out (64gb DDR5 ram, core i-9 13900k, 4Gb NVMe M.2 SSD), so unless you are doing CPU intensive things, any mid tier PC will be more than enough.
I've been down this road before.
The best thing any of us can do at home, besides repenting from trackpad contouring and apologizing for our sins, is absolutely maxing out internet speed.
Remote work for our jobs is mostly going to take place either through a cloud application (accessed through a browser), a Virtual Desktop environment, or a Remote Desktop environment (where you take over and control your office computer). In all of these scenarios, the bottleneck is server hardware (not under our control) and internet speed (between our home and the outside world, which is marginally under our control).
Assuming you're using a computer built after like, 2015, it would be unlikely that any hardware will make a difference in performance. Sure, if you're using a first gen Chromebook at home and you upgrade to a stock Dell from Best Buy, you'll notice a huge difference. But if you build a home rig with quad monitors that can run Crysis 2 at max specs...it's killing a house fly with a cannon.
Now, if you somehow scored a "thick client" at home, meaning you have an actual local install of whatever TPS your practice uses, hardware comes back into play. But I don't think this is a common situation. I have a laptop "from" Varian that was acquired shortly before I came to my current hospital, but it sounds like we bought it directly "from" Varian. I don't know how open any of the companies would be to taking a homebuilt device and putting their bread and butter software on it.
In short, OBVIOUSLY I'm a giant technology nerd, and my solution for peak home performance was getting the fastest internet available in my area.
(I mean, then I also created a wired ethernet network in my home, and run DoubleShot Pro with my primary desktop connected both on Wi-Fi and ethernet...)