Career dilemma for a young engineer!

Hey everyone,

I am a 26-27M Electrical and Computer Engineering (ECE) graduate from Greece. For the past 3 years, I’ve been working as a maintenance electrical engineer in a heavy industrial plant.

My long-term goal has been to move abroad, but after countless applications, I haven’t managed to land a direct job offer. Because of this, I decided to look into doing a Master’s degree as a stepping stone to integrate into the local job market. I’ve already applied to some top-tier universities in Germany (KIT, RWTH Aachen, FAU Erlangen—I'll get their decisions by late August), and I’m currently waitlisted for a great program at DTU in Denmark, where I’ll know the final outcome in the next 10 days.

The Problem:
I am completely burnt out at my current job. I don't enjoy it anymore, I dread waking up in the morning, and the projects aren't challenging or interesting. I absolutely need to leave.

Recently, I went through interviews for a position at a major Greek company (a huge corporation here), and they extended a genuinely great offer. Actually, they came in contact with me and I did no applications on this job.
If I accept it, it will definitely get me out of my current rut and provide a much-needed change of scenery. However, if I get accepted to the German universities in July/August, I am probably leaving for the Master’s. This means I might have to resign from the new company after barely 1–2 months (or potentially even right before my start date).
I’m really worried that doing this will make me look completely unreliable, get me "blacklisted" by one of the largest corporate groups in the country, and burn a major bridge for the future if I ever decide to move back to Greece.

On the personal side of things, my girlfriend currently lives and works permanently in Germany (though she has the flexibility to move back if I decide to stay in Greece).

What would you advise me to do?
- Should I accept the new job now just to escape my current situation and cross that bridge when I get to it, even with the risk of leaving in 2 months?
- Is the "blacklist" fear in major corporations a real thing if you resign early to pursue higher education abroad?

Any advice, insights, or similar experiences would be highly appreciated. Thanks!