One more ryzen calc "victim". Don't mean me wrong but I'm already tired of these threads. Most start with "I have a problem with memory on ryzen platform" and "I was trying ryzen calc". It's free, 3rd party application. Like any similar software tool, it may help or not; it's never guaranteed. Anyway, let's focus on the main issue.
Check these steps:
1. Clear CMOS
2. Set XMP and don't reboot
3. Set manually memory clock at 3600 and timings at 16-16-16-36
4. Set memory voltage at 1.35V (if it won't work then repeat with 1.40V)
(even if you tried then clear CMOS before, just to be sure)
2nd option:
1. Clear CMOS
2. Set manually 3600 / 16-16-16-36 / 1.35-1.40V
Both above steps were enough to set 3600 16-16-16 1.35V using GSkill Royal 3200 CL14-14-14 memory at 3600-3733 CL16-16-16 1.35V on Gigabyte X570-I Pro WiFi.
I can't find that but are there any diagnostic LEDs or anything like that? ... so you could check what is causing the issue
IF ratio should be automatically set to 1:1 up to 3600. However, to be sure set IF manually at 1800MHz.
Based on what I was testing, X570 Gigabyte motherboards are already optimized to handle 3600 without any issues as long as there is no problem with the CPU/IMC or memory itself.
If you won't make it boot at 3600 at all then it can be also the CPU. I had a case when 3700X couldn't work with one motherboard above 3200 and support of one larger motherboard vendor confirmed there is some percent of CPUs that won't run at more than 3200. It was like 3200 100% stable, 3333 barely booting and 3466+ couldn't boot at all. Different CPU or the same CPU on another motherboard could run at 4800+.
This is however a low chance and I would look for an issue somewhere else.
You can try downgrading BIOS 1-2 versions back as the latest one was adding memory compatibility improvements so they could mess something up with timing tables or something. The motherboard supports "no CPU" force flash option so it should also support downgrade without issues.