I finally got it.
It turns out there is an issue with the validation, but not only SSIS elements go through that validation, as stated in the fourth failed solution of the question.
The CONNECTIONS also get validated and have their own Delay Validation property, which needs to be set to true.
After that the excecution time went from 40+ mins or no running to less than a minute for the full process (This is just one step of a much bigger process)
I hope people with this same problem can find this solution easily because there’s a lot of people running into this problem and nearly no solutions posted online.
In a nutshell: Check that all your elements involved in the task, including the DB connections have Delay Verification Property set to True.