Like which?

AFAIK in Germany the TL;DR is that if there's anything in the EULA which violates "German Civil Code (BGB)", then either parts or all of the EULA are invalid. I remember that in Germany an EULA cannot prohibit reselling the software to somebody else, or making your own backup copy (kinda tricky nowadays though where everything is just a "service").

"AFAIK in Germany the TL;DR is that if there's anything in the EULA which violates "German Civil Code (BGB)", then either parts or all of the EULA are invalid. "

There is nothing unique about German law here. The same is true in the USA and most other countries. If a EULA or any other contract (whether agreed verbally, signed physically, digitally, or via a "click") violates the law, it can be considered invalid/unenforceable. It has nothing to do with how the agreement was agreed to, but with what the agreement contains. (There may be some legal theory that may carry some weight that a contract agreed to via a "click" is more likely to be unconscionable that one agreed to with a physical signature, but that does not automatically make all "click" agreements unenforceable.)

There are multiple reasons why an EULA may be viewed as unenforceable in the EU due to unfair terms: https://europa.eu/youreurope/citizens/consumers/unfair-treat...

Interestingly, Unity runs afoul of many of those.

That's just standard contract law in any country.

In which case you have no license to the code. So either way, you'd have no rights.

You're still welcome to contact them directly and try to get some kind of contract directly if you can't agree to the EULA for access.