€4k was really cheap, I'll risk.
You just stated what we should internalize more than ever: we can do something, even if if takes longer.
I'm in Europe too and dealing with shady/unwilling professionals forced me to wake up and start learning.
And never forget the skills we acquire for ourselves may one day prove of value to others. But just the sense of personal worth from getting something done or fixed is precious.
Ouch.
Meanwhile, in Portugal, my peak energy price will be around €.10, with the minimum at around €.06
To what degree is your house insulated already?