I've handled all of these. With no issue. If you mean "simultaneously" thankfully I don't edit 8K video simultaneously with programming and recoding music. I don't know anyone who does either.
My point is rather, "16GB in 2012, 16GB in 2022, no difference". And I say: try doing any of those things on your 2012 machine and a 16GB M1, and you'll immediately see the difference.
I didn't say there is "no difference" between these machines, that's ridiculous. My point is that Apples system-on-a-chip architecture, while giving big performance and efficiency gains, comes with a trade-off. That trade off is availability and pricing of RAM configurations. That 8GB or 16 works for you is great, but it doesn't work for every use case.
My point is rather, "16GB in 2012, 16GB in 2022, no difference". And I say: try doing any of those things on your 2012 machine and a 16GB M1, and you'll immediately see the difference.