While the Linux software ecosystem is not quite as smooth as macOS, I have found it to be quite adequate for my work.
64GB of ram apparently sells for around $600 right now, plus $500 for each 1080, plus $700 for a 16 core threadripper (I'm not sure what 32 core processor you're using or if you're using multiple processors, but the next gen threadripper will be 32 and cost about this much), plus $1000 for the base model Dell XPS 13 9370 puts you at a total of $3300 before we even get to the motherboard, case, monitors, keyboard, mouse, power supply, storage, laptop upgrades, etc. This also assumes that you built the desktop yourself while valuing the time you spent researching and building at $0.
Anyways, saying that your setup cost less than a MBP seems pretty ridiculous even if it is technically accurate when you only consider the "max" price of a MacBook pro.
But I really didn't check. The point is, the MBP's performance per dollar is ridiculous.
One of the best things about the Apple ecosystem (which I cannot even find in Windows) are the number of Mac focused publications that discuss and critique the variety of apps available. This has been damaged lately since most Mac apps are now discussed as extensions of their iOS ones, but it’s still beyond what I have found on Windows or Linux.
I also use zim wiki for notes taking.
Honestly though, email has lost a lot of utility for me in the last few years (privately; professional email is still strong), to the point where I am really fine with webmail these days.
I was very surprised to see how far linux has gotten as a desktop workstation. Including very good apps (darktable, ardour, inkscape and even gimp which had an horrible interface at the time).
I still think macOS had a superior UI (I say "had" because I haven't touched a mac since sierra) and that the hardware was beautiful. But my main workstation which has 3x 27'' monitors attached to it, was less than 2000$ (without the monitors of course).