Problems booting with XMP on.

XMP is an OC-profile. While it should work most of the times there is a chance that your ram just don't go fullspeed.
If the ram would not be 2yrs old I would say refund it and get a new one but...
There might also be some random support problems between the board and the ram.

What you could try to do if you have some free time and the hunger for faster ram is, that you oc the ram by yourself with little stepps. There are a lot of tutorials for this out there.

Did you overclock your CPU? Rarely a borderline unstable OC will render the RAM unstable too.

Intel CPUs aren't significantly affected by RAM speeds, at least in games. You're not missing out a lot.

You can try to manually change the frequency and timings in the BIOS instead of using the automatic XMP profile. This will let you fine-tune the speed so it's not quite as fast as the XMP setting, but it's faster than the stock. The frequency and CAS latency are the most important things that need to be changed, and the ones advertised for your RAM are 3200MHz and CAS 16. If you manually change to those (and it boots fine), then you're very close to what the XMP profile would be.

There are other timings too, but you would need to know what the exact model of your RAM is to be able to set these properly. You can experiment if you want to though, reducing timings by small amounts like 2 or 3 won't damage your RAM. In the worst case you would need to reset your CMOS which will return everything to default (your motherboard has a handy button for that, above the USB ports on the back).

If it doesn't boot at 3200 CAS16, you can try 3000 CAS16. It's not as fast, but a lower frequency will be more stable. Alternatively increase the CAS latency to 17.

You can also increase the RAM voltage marginally as well. If you only increase by <0.5V it will have a tiny effect on temperature and none on longevity, but it might make it more stable. DDR4 RAM voltage is either 1.2 or 1.35V, so check which one your RAM is using. You can find out in the BIOS or using CPU-Z. A voltage increase by itself might render the XMP profile stable.

Make sure your Bios is up to date, I had something similar happen when changing RAM, after turning on XMP, it wouldn't boot correctly,
luckily a Bios flash to the latest version fixed it.

Reset Bios to defaults. I assume you already did that.

Did you carefully read the text when enabling the XMP profile? Make sure that it doesn't also automatically apply some weird built-in overclocking profile to the CPU. My Asus Z270 would do that for some reason unless you selected 'no' in the following screen.

You could try to set the timings by hand instead of using a XMP profile. Check this list, find your exact part no. (page 5 for DDR4 3200) and set the corresponding timings you see there.

sometimes XMP profiles are broken(wrong settings). Sometimes faulty RAM works on stock, while on XMP makes crashes.

I think setting RAM timing manually(+OC) is better than XMP

For example my Ballistix Sport LT on both XMP is 3000MHZ timings 16-16-16-35, while OC'ed easily goes to 3600/16-19-16-36 at 1.35V!

the first thing would be to update your bios but it seems like you did that already.
when you enable xmp you need to turn everything memory related to auto. especially timings and voltage obviously. higher performance ram needs more voltage to run the xmp settings.

so you turn on your computer, it runs for a few seconds, turns off again, turns on and runs normally. right?
what's the ram clock after that? is it the higher xmp clock or is it back to standard clock?

if it's back to the standard speed the xmp profile seems bad and you will need to punch in the settings into the bios manually.

if it's on the higher xmp clock that extra reboot is just the memory controller retraining every single time.
i don't know about intel but asus amd boards have a fast boot option to disable memory retraining every time the system shuts down completely or loses power. enable fast boot and see what happens.