I'm currently working in a startup that's incubated inside a much bigger company. We are a team of 4 people, including the leader (aka product owner). Our leader is a long time developer who has 15+ years of development experience, our data analysis guy also has 15+ year of experience, but, has a LOT more knowledge due to study and multiple graduations (I would say he is more of an academic person), and then there is me and another junior developer. Everyone gets along well and we could be called "friends" at this point, including the lead.

The problem we're facing is our leader's resistance to our ideas. The project itself is very young (less than six months in development) and everyone has a better idea on how to do certain things, but when presenting them to the leader, although very open to debate, he is extremely resistant to suggestions. We've multiple times come up to him with solutions, backed up by articles, evidences and studies, and we're still faced with a long debate on (sometimes) obvious topics. In the end the idea is neglected and the product ends up being a shadow that what it could have been.

I've "lost" a debate to him for the third time in a extremely obvious topic, and I'm starting to feel like it's better to just proceed in a wrong path and let it break at some point than to enter in another pointless debate. My coworkers have faced this problem aswell, more than I have and sometimes with harsher resistance, and that's why I decided to post this, because I don't think that's how startups should work.

How can I and the team approach this resistance? Should I give feedback to him about how the team feels about this issue? If so, should it be a group meeting or a one to one talk?

Note: He is ansious during debates and doesn't let you finish, he talks 70% of the time while you talk 30%.