Hi Niky,
The fact that you cannot connect pipes with an elbow at such a small angle is actually just default Revit behaviour, so there is no way solve this with Dynamo either. One solution that I can think of is that you just connect the pipes without a fitting (assuming that what’s being built is actually just a bent pipe with a huge radius?).
Here’s a post with some code that might help: Invalid Duct/Pipe Connections - #10 by T_Pover