I was lucky enough to get tickets to see a game at the Maksimir Stadium, but flights were really expensive so we are flying to Budapest and driving a rental. Where is it recommended to park near the stadium on match day? It will be a weekday if that helps, and I don't mind paying, or walking ~15mins / getting transport?
I guess tickets are for one on Champions League games? There are some parking spaces close to stadium by there will be occupied by locals and guests with VIP passes. I suggest to you to park on one of the big peripheral parking spaces and travel to stadium by tram because all parking spaces close to stadium will be occupied long time before you arrive. Police will probably implement special traffic regulation and close roads close to stadium and divert all traffic. In short area around the stadium will become impossible to navigate.
There is big parking space south of main railway station. From there you can take tram no 5 straight to Maksimir. It that one is full you can park on huge parking west of modern arts gallery and take tram no. 7.
Be careful to pay for parking because if you don’t pay local parking company will send fine to lawyer in your country for collection and he will add hefty fee (100 euros or more). Parking is dirt cheap in parking places I recommended so there is no need to risk it.