There used to be several apps available that worked with multiple dashcams, but the dashcam manufacturers keep adding new features, changing the app interfaces, and then the general purpose apps either don't work or don't support the new features, so you end up needing to use the manufacturer app anyway. For someone to keep their app up to date for all current dashcams would be a huge amount of work, and most people want the app for free, so they are not going to sell enough.
It would be nice if the dashcam manufacturers could all get together and define a standard app interface that they all comply with, and while they are at it, a standard cloud server interface that they all comply with, then we could have multiple third party apps and third party clouds, maybe partly funded by the dashcam manufacturers so free the customers, at least for the basic functions, with maybe charges for more advanced features like cloud storage.
I don't see it happening though, the apps are part of what the manufacturers are selling, a good app helps sell the dashcams, bad apps push customers to move to the better manufacturers, there is not much incentive for them to cooperate, and no agreement on what cloud services should be provided or how they should be paid for. Nextbase iQ is sold on its "fantastic" cloud features that they wouldn't want to share with anyone, but most people have no interest in them, and years after announcement, their somewhat expensive Roadwatch AI that people have been paying a subscription of £9.99 per month (£119.88 per year) for, is still in the state of "*Coming Soon" - good money for something that doesn't