Today the
Mavic 2 series is considered as old (

) ... wouldn't expect any craft firmware update releases, it it what it is today. Furthermore the app you use with it is DJI GO 4 ... which also is something no newer model use, all so far have been released with the DJI FLY app instead, even the
Mavic 3 ... so don't expect something serious to be changed in the app either.
The DJI Assistant program for the
Mavic 2 series is most probably treated in a similar way by DJI as the craft firmware & the app ... DJI focus on the newer models now, so if you want to use it you need to get compatible equipment.
Also when it comes to the DJI Assistant ... it's not much to explore there. You mainly have 2 useful functions & one of no use to you.
-There you can check for & update the craft & controller firmware's by connecting the craft or controller via usb to your computer ... but as I said don't expect that DJI will release anything new for an older model, and the GO 4 app will be able to see & update your hardware if something new will be released.
-You can in Assistant also calibrate the vision sensors ... can be needed sometimes & the app usually tells you if that's necessary. Don't really know of any alternative to calibrate elsewhere than in Assistant ... so if the need arises you will need to get access to DJI Assistant.
-You can also there extract the flight logs stored in the
Mavic 2 itself ... but they aren't of any use to you as they are encrypted & can only be read by DJI staff.