I had 10700, 10850 and then 12600 and 12600 was much much better than even 10850, it noticeable even in windows.

But if I need only few files from backup Windows backup doesn`t provide such options.

It depends. For me 2 stoppers: can not automatically created backup in background and can not get any separate files or folders from backup.

7400 works also, but depends on motherboard. On my I was able to get 7000 but fully stable

Buy 1500 and close this question for 10 years.

Always buy x2 from your maximum power utilization.

And which timings did you have on 13600 and now?

It depends motherboard, ram and memory controller in cpu. My friend has 13900k and ram runs on 8000 with all timings manually decreased, I have 13700k and the same ram works on 7200, but I have another motherboard