TLDR: I would like guidance on how to proceed with marriage when my father refuses to consider a suitable match for cultural reasons and is unwilling to engage in any mediation, including with an imam.
I am reaching out because I have been facing a problem with my family for almost a year now regarding my choice of spouse inshallah. I met and was pleased with a brother in April of 2025. I first informed my mother in early May as she was going to hajj and I would like to for her to make do for me. She had no reservations so I then told my father who refused to meet the guy as he’s from a different country than us.
He then asked for my uncle to get to know this brother yet my uncle has his own reservations. My dad reached out to my uncle regarding this matter months later (October). He said that he’s willing to engage with him yet before doing that, he’d like an impartial party to observe this brother and his intentions suggesting a vetting process. 
At first my uncle wanted Simo to talk to one of my friends – he did, yet when my uncle and my friend exchanged contact info he said that he was busy and didn’t have time to speak with her. So I then offered him to speak to my sister. After that conversation, he said that my sister didn’t have substantive information. So then I offered an imam (in December). I went and spoke to an imam, the imam spoke to the brother, and it’s 3 going on 4 months since I’ve spoken to the imam and my uncle has yet to reach out.
The imam said that he’d be happy to either talk to my uncle or my parents and since my uncle had yet to reach out I had one last conversation with my parents after countless dua for my father’s heart to soften, and he refused to speak to anybody including an imam, essentially the conversation went really badly and it’s unlikely that he will change his mind. My mother has also adopted his stance.
Furthermore, after a number of exchanges with my uncle, things have still stalled and me and this brother would like to make things halal inshallah. 
I still continue to make dua as although my parents and I don’t have the best relationship I understand how Islam is keen on respecting parents and keeping ties with kinship, etc. I would just love an outside perspective regarding if there are any alternative ways to move forward as although my uncle has said he can help, it’s also unlikely that he would take that wali role as he may not want to go against my father. Would my father’s refusal in this situation be considered unjust prevention and if so, what would be the correct way to proceed Islamically? Any guidance on the matter would be amazing. JazakAllahu khayran for your time and I hope you have a great rest of your day. Thanks.