Full screen Apple CarPlay mode option

I would not think an app has control over that. That's a function of Apple Play and the Infotainment System Hardware.

 

I don't think that's possible. Carplay has been designed to be non intrusive.

 

By definition, something is intrusive if the user doesn't want it. Here, the user (both OP and I) want it (as do some users who posted about it on Reddit), but we are not able to get what we want, so it's a lack of a desirable feature. Whether it's Toyota or Apple or both that need to implement it, the user doesn't care. Nor do we care what the reasons were for not providing that feature in the first place. As a software developer, it's certainly possible. There's no reason not to implement it or at least increase the CarPlay screen real estate as an option/setting. You could even default to the current display configuration (because certainly not everyone would want the same thing).