AMD Ryzen 5 5600X Processor (6C/12T, 35MB Cache, up to 4.6 GHz Max Boost) - £150.96 @ Amazon

Of course, AMD accidentally on purpose confused the naming by previously having non-X chips not being the same, but APUs with the graphics disabled- meaning poorer caches and older cores. Tech fans really need to be on the ball at all times, so they can take advantage of real bargains like the much cheaper 5600 non-X.

No it wasn't.

Depends on the prices at the time. If there's barely any difference, may as well get the X for better out of the box performance.
If there is a bigger price gap, the non-X is the better choice, especially for those that'll do a bit of tweaking.

They're still making Zen3 chips and boards, so not legacy at all. No one wants Zen4 with the board costs and small perf gains.

Depends on what you want it for. High-end gaming with overclocking or sending emails

What you got it clocked to about 4.7GHz base clock? Ideally you want it fix clocked to more than the turbo clock if you want the max performance. So 4.7GHz would be ideal.

3090 is doing the heavy lifting with deep learning though. That's a decent GPU for deep learning at home. Doesn't trouble an A100 but they cost rather more of course (edited)

The 3600 is a really good chip for that price. Too future proof it a little bit get the 5600x for around £130-40. For a GPU a 1060 6gb is a good option. I had a 3600 with 570 8gb. My pc system load times were a little slow. Don't know what was slowing it down, GPU or CPU. My guess would be GPU. (edited)