I have an 7" Aliexpress version I got for ~$230 a few years ago. It has built in Wireless CarPlay and works reasonably well. Virtually no drop outs (compared to a USB dongle in another car), although occasionally you need to reset the Bluetooth connection from the phone before it wants to connect. Volume controls suck compared to our Mazda which sets and remembers different value levels for phone, music and nav vs the single control I have on my unit. This means I have to turn it up massively for calls (which otherwise work fine) then smash it back down when I end a call before the music blares out too loud! Also... the screen barely bright enough in direct light...

But, for the price it works acceptably enough that I haven't bothered replacing it... I consider it, but not enough to spend money.

I did need to replace the OEM reverse camera (used for the factory RNS510) for a version that does composite connection instead. It's a step down in quality going from RGB to composite, but it gets the job done well enough... it's not like you need super high def reversing camera... and if you go down the RCD330 route it uses that same composite camera anyway.

That GT Zone unit looks like it also does wireless CarPlay (or Android Auto) out of the box now too... I'm tempted to have a look at how it treats volume control and how the screen works in daylight. It would also be a step up from 7" to 9" which is always nice.

From an installation point of view, even the stock units are 95% plug and play (except maybe the reverse camera depending on how it's triggered) for these types of units. You don't typically need VCDS (or similar) to code them in.

On the mic side, if it the unit has it's own Bluetooth (which is does for Wireless CarPlay/Android Auto) it won't be using the factory mic since that's connected to the Bluetooth unit under the seat. If the unit has an external mic input you *might* be able to repurpose the factory mic (or at least install a better something in its place).