So far the best option IMO is to retro fit some series 1 trim to a series 2, then there is far more options for an after market unit.
Make use of the Aerpro facia (now available in dual zone).
Dig Options for those who run Anroid phones is good.
By retro fitting the series 1 trim, it future proofs your car a little better. The series 1 has a far simpler fitment and design, so this means you don't have to wait around for a vehicle specific headunit to be designed.
The series 2 had the screen that comes up higher than the head unit, which mostly sits at the bottom half. That limits your selections heavily because you need a head unit and screen to be seperate and at this point, anyone would struggle to find that.
Head units almost always have the screen as part of it.
There are headunits like Alpines' Halo but then no one makes an adaptor facia specific for the series 2 for that head unit. 3D printing would be handy for this.
I prefer driving my VZ because it has CarPlay, to the VE with a series 2 headunit.