If you want inbuilt nav you are pretty much locked down to the Alpine, and honestly the UI is shit and they are way overpriced.
Look into something Android Auto (wired or wireless) and use your phone for maps. That way itll be live updated and more reliable with traffic as well.
Personally i'd lean towards the Kenwood DMX8020S or higher (DMX8520DABS, DDX9020DABS). They both have 3 rev cam inputs, Android Auto/Carplay, SWC support and excellent sound quality (4v outputs iirc).
Pioneer also make a nice unit, DMHZ6350BT. Its a super compact wireless/wired Carplay/AA unit, 4v outputs, plethora of sound tuning options, however I personally find that there is too much going on with the UI and its not as fluid as the Kenwood.
Sony XAV-AX5500 is also a notable contender, sound and screen quality are great but lacks in features compared to the other two when you compare the price points.
And if all that fails I guess you could go an alibaba android based cheapo