I have a Note 8, but rarely use it to fly my Spark*. I also have a cheap 6" Android tablet (see my sig) that I've dedicated to that purpose. I do, however, have the DJI GO 4 app installed on the Note 8, and it works fine with
the OTG cable. In my experience the order of connecting and turning on the RC doesn't matter, but my normal startup routine is to plug the cable into the device and RC, turn on the RC, and wait for DJI GO 4 app to automatically start.
Once in a very great while, the app doesn't auto start and when I launch it, it indicates that it's not connected to the RC. Unplugging and re-plugging the cable into the Note resolves that immediately.
My Note 8 is running Oreo 8.0, Samsung Experience 9, is
not rooted, and I get the same results whether USB Debugging is enabled or disabled in Developer Options.
My observations on this forum are purely anecdotal, but I rarely see US-based Samsung users having problems. I know that the US versions all have Qualcomm Snapdragon processors, while the non-US models use Samsung's own Exynos processors. I can't help but wonder if that's related.
* My Note 8 doesn't fit the grips with the case it's currently wearing and I don't want to remove it every time I fly. I've since purchased a mount that may make the Note 8 a better option, especially in bright sunlight.