I wish I could fix the garage front door water leak so I could fix the freaking side insulation that is ruined from the water seeping trough the garage door.
The major thermal loss is that exact whole 4 square meter of wall insulation that is ruined and moldy. And I can do that as it's not very expensive (200$ max) but fixing the garage door first is out of my budget and I can't do without it otherwise the new insulation will also be ruined.

There are two solution to fix the water issue.
The least costly is to add a porch at the level of the garage and that would add thermal cavities where I need to drill, except if I made it from grounded wood pillars, in any case it's around 1~2K.
Or change the garage door and fix the concrete abomination which would cost between 2 and 3k.