The card will be fine. 90MB/s is 90 megabytes/s which translates to 172 megabits/s (8 bits in 1 byte). Mavic 2 is 100mb/s bitrate... This is bits not bytes.
B = bytes
b = bits
B is not equal to b
The install from my Macbook went smoothly..... It downloaded the updated firmware w/o issues on the first try. It's on the same wifi network as my phone (which failed). Not sure why yours stop at 24%. Try removing the program and reinstall?
I was able to get sacrifice my macbook and installed Assist. Took about 45 mins for me to install software and upgrade bird and controller. What a pain. It wasn't that difficult w/ my previous DJI products (Phantom3, Mavic Pro, Spark)
Same problem. Tried to install Assistant program for Windows 10 and my AV quarantined it. I'm a little afraid it's infected somehow being that this is software from China. :/ Now what?
Got the Zoom... well actually my GF ordered it for me as a surprise so I didn't really have an option... no complaints! I don't do post anyways.... I don't have the patience for that. :)
Your "older" batteries are probably not holding 100% capacity anymore.... thus the longer flight times w/ the newer batteries. Have you tried to use the newer batteries w/ the older Mavics and test?