So as title suggests, the machine is an HX, e61 group that I started after some 6 months of use at my parents place, and it produces very different coffee than before and I found out that water is not as hot as before. It seems slightly colder.

These are the things I thought might be responsible:

1.before that I cleaned the head, I removed the top bolt to clean it up, and then I removed the lever next to the head that you raise when starting the water, but while I was loosening it, I didn't put it to the open or half position or whatever it is supposed be in, so you can easily slide it out, but as I left it in the closed position, it was stuck like some part was pressing on it and it was really hard to take it off, and it was actually so hard that it made me little worried that some part can be bent of affected... so I am thinking something was loosened or changed the shape??? i know it may be confusing, but if you see this video and go to 1:25 sec. time, you will see what I am talking about:
2.second reason could be that something happened inside the boiler since the was was left there even tho I let some out, however I suspect my parents could be using it with tap water that is very very calcified and I thought it calcified the boiler possibly? the mushroom wasn't calcified.... but they said they didn't use it and I used always silica filters (even tho, one was left there for few months too....not sure it's ok)

I tried to put thermostat so there was about 1.5bar in the boiler and water was still not as hot as before, coffee was weak and crema was very white and thin, where before the whole cup was almost crema...and no it wasn't due to the coffee type, it was due to the machine....

so any pointers what would I check or look out to restore it to the great coffee it made before It was resting unused for those 6 months?