With the recent Intel price drops and the fact that Adobe software generally has had the edge on Intel CPUs,something like a £185 Core i5 10600K or £240 Core i7 10700F makes more sense. Even if Zen3 is slightly faster,it isn't really worth the large price increase
IMHO. Even the chart shown in this thread shows this!
Also,another thing is that both Zen2 and Zen3 seem to benefit a bit more than Intel,when it comes to having higher speed DDR4. So,unless the OP wants to buy some new DDR4,their 3000MHZ kit will probably not be ideal especially for Zen3.
Plus reading some of the earlier replies,I agree maybe getting a new motherboard makes more sense ATM. DDR5 is coming out late this year/early next year so maybe its worth also investing into whatever new Intel or AMD platform is out then??