Not sure quite what you mean, but thanks for the pointer.
I contacted the manufacturer who said there's no HDMI interface available, and no example code for Arduino.. so I'm like wtf?
MIPI is a set of specifications, as far a I know. MIPI DSI a specification for differential serial signals, afaik. And the connector looks like for MIPI DSI, I think.
There is at least one STM32 processor that has direct driving capabilities for MIPI DSI, with an embedded display driving module, but I don't remember which one.
I would never (again) buy such a display without a signal conversion board for it, e.g. from HDMI.
Any TFT or STM32 expert may correct me or provide additional information.