spdif is not an option on these cars. the entire system is a low level analog type system.
there are very few spdif amplifiers on the market anywhere, but multiple dsp's have a spdif input that can then be routed to wear it needs to go.
honestly, spdif has no real benefit in the car unless you've got noise issues and have already exhausted every other potential remedy.
i quickly pulled up this unit in a search:
https://www.eonon.com/Android-Car-GP...-from-ADI.html
it's important to note that it's 'built in dsp' is no different than most other non-android aftermarket radio's. my pioneer 80prs has most of the same audio tuning features--it doesn't have sound effects or sound fields, which i don't use in my home theater setup either...