do you think it's possible that Dji will either make the mini pro 3 work with the smart controller as in being backwards compatible like they did with the air 2s ?
I am thinking of purchasing one but I already have the smart controller so I don't know whether to purchase the new RC controller or just the drone

You pose a good question. Hopefully DJI is considering this.

Personally, I've been wondering if DJI will make the RC Pro controller compatible with the Mini 3.  Seems if they can make it compatible with the Air 2S it shouldn't be that hard to make it compatible with the Mini 3.  I much prefer to use the RC Pro over the RC as it is better built and has more functions and capabilities.  

Hello there tvp62. Good day and thank you for the inquiry. As of the moment, we do not have any information with DJI's future updates and compatibilities for the DJI Mini 3 Pro and with the DJI Smart Controller and with regards to this matter. Kindly please stay tuned to the latest updates by subscribing to DJI official website at www.dji.com . Thank you.

three different controller options working with one drone....that would make sense if dji has plans to do this for every drone going forward.  first the m3, next the m3p.