Speed call outs are only made for sequencing…ATC does not give you reminders that there is a speed restriction below 10000’ or within certain airspace classes. You are expected to know and follow those rules.
Speed call outs are already in the sim ATC but for GA rarely make sense. If your aircraft going downhill at full power will barely scratch 200 KIAS you won’t bust the 220 limit you often get from ATC.
IRL ATC on occasion may also ask for certain speeds above “normal” such as maintain 120 until IM or short final when you are flying an ILS approach in a C-172 with big-iron traffic following you.
Not sure how feasible that would be in the sim.