2600K is legendary, but it can’t drive modern high end GPUs anymore. You’ll get a big increase in performance when you upgrade. Considering a 5600X is much faster than a 2600k, I think you’ll love Zen 4.My 2011-built 4.6 Ghz Sandy Bridge system is still going strong - albeit with an RTX 3080 upgrade (and a GTX 1070 upgrade before that).
I would have upgraded the CPU and mobo along the way, but impressive gains were never offered by Intel or AMD until recently. Zen 4 will be my next upgrade.