2015 XC60 D3 - Coolant crazies me

[MKG]

Hi everyone, hope you are doing well

And hope you are doing better than me, I am a little crazy with a long long coolant leak problem on my 2015 XC60 D3 (D4204T4 engine).

The problem became at the beginning of this summer, during a 7-days trip. Coolant became+ to be lower and lower and finally the "Coolant low Stop" warning appeared on the dashboard.
After filling it with water, the next day the warning appeared again, so I went to the first shop I found, explained my problem, and they gave me a (supposed) Volvo-compatible blue coolant and put and anti-leaking product (K-Seal).
The problem was increasing, and sometimes the tank appeared at the morning totally empty.
Then second Shop, they reviewed the car, pressurized the system, run the car a lot, no leaks found.

3 days after, "Coolant low Stop" light again. I became to see see foam on the expansion tank, mostly after intense driving (boosting).
I start to read a lot in forums related to head gasket problems creating foam and bubbles on coolant. Scared... Review oil.. is perfect. Coolant does not seem to have oil, but I discovered that coolant makes foam "by itself": If I extract some coolant from the reservoir and shake it in a bottle, it makes a persistent foam (seems soap for cleaning dishes, not coolant).

So once I arrived home, I decided to totally replace the coolant with a new one, purging the circuit using the valve located below radiator, adding liters and liters of distilled water. And driving for allowing the thermostat to open and extract the old coolant that could remain in the circuit, so I also where in parallel trying to locate leaks.
Finally, using a UV lamp, I could find rests of coolant in the base of the car, below the the expansion tank. ¿probably spilled out from it due to excess or pressure? Scared again, I tried a CO2 test for detecting combustion gases.. negative.

When I thought that the coolant circuit were enough clean, and I see that the old blue coolant where replaced with a green new one, I went to a local reputed Shop.
They pressurize system, made an own CO2 review, EGR review. Nothing. Finally they changed the expansion tank cap, and gave me it again to test it.

My test was driving it 5 hours, city and freeway normal running. OK.
The next day coolant seems lower than previous one, so I run it during 1 hour but at high rpm (2500 to 3000, never more). OK... but I notice some foam on coolant again.
3rd day, 40 minutes of city driven, traffic jam. I arrive to home normally and after 1 hour I check coolant and... I find this:

A good quantity of coolant spilled out, 100 ml or more. Just below the passenger wheel. It must have been spit out from the expansion tank.

Try to demonstrate that... next day, engine cool, refill tank and 40 min of city drive. Boosting and high rpm.
What I got? Foam on the new coolant. And, when I tried to see I the coolant is bubbling, opening slowly and carefully the reservoir cup... it became to spill out from the expansion tank security valve (see https://1drv.ms/v/s!AuaizMDVt9_hgnjlqJs8Sq_TUqEj).

Typically, it points to head gasket problem (aaag!). When engine is cold, I extracted some coolant and shook it, foam appears again, but much less than at the beginning, which indicates that changing the coolant is in good way.
So, another coolant circuit cleaning process and repeat stress tests.

- Test: Engine cold, trying to see coolant bubbling. I detect lot of small bubbles not when accelerating and when releasing the thortle (see video)
https://1drv.ms/v/s!AuaizMDVt9_hgxwGBsLPQfzvXcqH

- Test: Engine cold, coolant exactly at MAX line. Freeway normal driving during 30 min. Stop and check coolant. No foam, but the reservoir tank seems to be totally full. I carefully open the cup, but it spills out some coolant and indeed, the reservoir tank is totally full!!. And with engine idle, I can see how the coolant level changes up and down and what seems big bubbles moving up

https://1drv.ms/v/s!AuaizMDVt9_hgxgimb8ZfU0pjiUU

How could it be possible? 30 minutes before, when the engine where totally cold, the coolant level where normal. Air in the circuit? -some days before I heard inside the car those typical "burping" noises like air circulation in hoses-
6 hours later, coolant level have returned to normal MAX level.

I am really really crazy with this situation. In other hands, the car runs perfectly, smooth, no excess of diesel consumption, no smokes.. perfect.

Do you think that I have a head gasket / cracked cylinder problem?
I'm quite sure that the problem is related to air in the circuit (injected by engine or injected by other component). Could it be EGR or water pump?

Any suggestion will be appreciated, and sorry a lot by the big post.