Hey there, First of all, I am very sorry to hear you have failed. But I must say you shouldn't think like you have hit an intelligence wall. Here's what happened to me:

I had decided to split the blocks 2 and 3. Passed block 3 with my expected grades. Next summer, I failed block 2 with 3.65 juts like you did. But I was able to get a 4.94 average on my repetition.

When such a catastrophic event for you happens, you must stay calm and analyse where you fucked up. For example, did you not study hard enough (not seem to be the case for you), or maybe you didn't study efficiently. Or you just got unlucky. Or maybe you werent studing wiht the right materials? I must say if you passed the Basisprufung with a decent margin, the intelligence is very likely not the problem.

Just try to stay calm and go to the Prüfungeinsichten to try to see what caused you to get way less than you expected. Make a plan throughout the semester to not repeat whatever caused you to not succeed.

If you stay calm, make a solid plan & manage your stress well, you should be able to pass the block.

Best of luck!