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Is this a good enough overclock? Did I get a bit lucky/unlucky with the silicon lottery? And can I improve my overclock a bit more?
The answer to your questions aren't easy because people overclock for different reasons: some to eek out just a
little bit more performance with optimized settings that take advantage of manufacturing tolerances, some as a demonstration of what it can do even if impractical, some just because they like to tweak their computer. In short: anything that works for you is a good enough overclock, but if you've never found the limits of stability then it can probably do a bit more.
If you wonder if it will it degrade your system sooner the answer is yes, absolutely. How long will it last? nobody knows but keeping it below the 90-95C band is the best way to help it last 6-8 years. Or at least until it's no longer able to serve it's intended purpose with newer softwares...the usual time to go all-in on a major upgrade.
The one thing I'd advise is set it up in full stock with BIOS settings, maybe with PBO enabled, and take a controlled measure of it's performance with benchmarks. Cinebench would be good, ST and three runs of MT back-to-back. Make sure there are no background apps running...not even RyzenMaster or HWINfo. Then set it up with your overclock settings (again, using BIOS so RM doesn't ever have to run) and make the same benchmarks in the exact same conditions.
BTW: when you're done with experimenting with RM uninstall it. Use only BIOS settings for your OC whichever you use. The RM service is known to harm performance even if not using the utility. It was never intended as a 24/7 utility anyway but as a tool for dynamically testing settings within the OS primarily to help with overclocking demonstrations for overclocking competitions.