I think I have this sorted out, benchmarks are above spec so no complaints and after many hours I'm not going to try and go higher in OC. I *think* the problem was RAM timings. The default DOCP profile was setting ram (which is native 3600-16-19-19-39) to 3603MHz which means the fabric was 1802. From what I have read, when Ryzen fabric is >1800 you lose the 1:1 coupling resulting in worse performance unless you get to very fast overclock levels.
I spent hours trying to sort this out. Manually setting RAM to 3600 and fabric to 1800 caused the PC not to post. I had to pull the CMOS battery and disconnect all my drives to get it to post again. Did this song and dance many times before I landed on a CPU OC that worked with RAM set to 3533MHz (CL16-19-19-39) and fabric set to 1767. This keeps it at 1:1, and gets my RAM very close to spec.
The biggest issue for me was single core performance numbers, which went from about 420-430 up to 545 on Cinebench 20 (4826 multi). Rest of the benchmarks look good too.
UserBenchmark : https://imgur.com/a/hICPmEq
PassMark : https://imgur.com/a/lRp5NHf
RyzenMaster : https://imgur.com/a/A9wGwQK