Hi @sree_vardhan_ra,
There's no plan to decommission ACS.
You can take a look at ACC v8 documentation on some of the information you're looking: ACC V8 and ACC v8 with AJO ACC v8 with AJO
Regarding ACC vs ACS vs Marketo you will have to look at business use cases you are trying to solve and then come up with which product is best fit based on the needs.
@swadhwa
Thanks, SK!
Thanks, Sathees