I overclocked my R7 1700 to 3.8 GHz by only changing the multiplier. Voltage is at 1.208V stock / auto. Temps with a Thermalright Macho X2 don't exceed 61°c when stress testing with prime95.

With the stock cooler, 3.6 GHz is probably the sweet spot, but your voltage seems pretty high, so do your temperatures. I personally wouldn't want to go beyond 70°c for a daily use overclock.

But: ASUS motherboards are not the best for Ryzen in my opinion. I had a PRIME X370-PRO and even after 20 BIOS upgrades, I still couldn't run my RAM at DOCP with 3200 CL14. Voltages were higher and there is no option to re-enable Cool'n'quiet when the CPU is overclocked.

Now I have an MSI X370 Gaming Plus which I am much happier with. RAM is stable at DOCP, voltages are lower and I can enable Cool'n'quiet, so depending on the power plan, the CPU jumps between 1.5 and 3.8 GHz and the voltage between 0.4 and 1.2V.