This begs the question. What is the oldest hardware that can boot modern Linux but still be used as a daily driver?
You need to both decrypt and decode all at above the framerate of the video, doubt that will be doable on any older hardware, unless ssid hardware has dedicated components for those functions.
If I had to implement this on an old CPU I would likely be passing network, video and encryption off to co-processors and the older chip will effectively only be running control information.
But that that point why not just use a modern low power chip.
Only slightly noticeable waiting times when I accessed some sites, but it worked and the application works too.
Linux Mint Vanessa, running the Mate DE.
The program is a C program with a single Makefile. My workflow was (and still is, even on my desktop) using a Vim with three vertical splits:
1. A LHS split which is a terminal to run make and execute the program for testing
2. A RHS split with the program source code (single file program).
3. A middle split with the test input file and test output file (in horizontal splits).
Although it is just a single file, on my other C projects I've used the same laptop, with the same 3-vert-split Vim, with multiple tabs, so up to maybe 16-20 source files open at a time for a single project.
Building C projects is very fast, even on the Core 2 Duo/2GB RAM setup. Running a similar workflow but in VSCode on my desktop is less snappier than Vim on the laptop.
I haven't tried doing a Go project on that laptop yet with VSCode, but I am tempted to see what happens :-)
But now I can tell why you're experience was good. Mate is a phenomenal desktop environment certainly, so 2GB is probably more than enough for a daily driver.
I think you'd want to aim somewhere around the Pentium 4 / Athlon XP era. The docs say it doesn't support the original Pentium, so I suppose you could go back as far as the Pentium II if you really want to suffer.