The main "daily driver" constraint is probably the crypto required to access most modern websites. You can make the leanest and meanest system you can to run great on the slowest machine but the internet is nowadays an unforgiving place.
Video delivered in real time over an encrypted connection, this is a double whammy.
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.
Assuming "daily driver" requires a modern web browser running modern web productivity apps I'd put the minimum at a Core 2 Duo with 4 GB memory. It wouldn't exactly be snappy but with a bit of patience you shouldn't be limited by the hardware. Throw in a GPU with hardware video decoding and you might even be able to watch YouTube in above-potato quality.
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 :-)
I tried Fedora (Gnome) on a 2GB machine and it was struggling a bit (mind you, there were several services, such as PackageKit, taking too many resources).
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.
For the sake of argument, let's say a computer where you can install Debian 12 and run a WM and a browser, and it's not excruciatingly slow.
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.
3 years ago I tried to run any modern distro on Pentium 3 (without compiling anything by myself). It appeared I wasn't able due to "invalid opcode" error inside systemd. I switched to Devuan (Debian fork without systemd) and it boot and was as usable as first raspberry pie.
Definitely not modern Linux, when I got Slackware 2.0 in 1995's Summer, I owned a Pentium 75Mhz, with 8MB RAM, Trident card capable of 1024x768 (X could only handle 800x600 on it), IDE CD-ROM and HDD.