Rx 570 has own power supply and OC-ing it has nothing to do with motherboard, it's done using SW, there's nothing in BIOS to OC it.
Yes 3600 can be OC-ed just need better than OEM cooling and to watch for voltages.
Eh, you can. All you really need is good cooling solution (at least a very good single tower 120mm), luck in silicon lottery, and some gumption. Your motherboard has the feature, might as well do it for the experience. You're likely to be limited on silicon lottery and/or cooling as well. Now, how well you can do overclocking is another question entirely.
Find FIT voltage, set voltage to a bit lower than FIT (do not go any higher than FIT), see how far that voltage gets you in clocks. Do benchmarks as well to see if you gained anything from that. If you're lucky with the chip, you can see lower temps and higher clocks; benchmark gains possible but not guaranteed.
If you got unlucky, then just enable PBO with that nice cooler you have and let the chip do its thing.
Keep in mind that Ryzen is poor for overclocking; increases in clocks don't translate to linear performance especially in games. Benchmarks, sure. Plus Ryzens boost high out of the box when paired with capable cooling, a tiny bit more when PBO is maxed out.
Even AMD realized that the potential is doing it the other way; by optimizing voltage to control temps and let the algorithm do the job. Hence we got PBO2 with Zen 3.