Regarding SuperDuper!, Dave Nanian is very responsive, and he will let you know some more details, if there are any.
Regarding the time frame, in actuality, these releases are the same as I have seen before. Most apps are compatible when the initial non-beta version comes out, but then at least for me, the order of remaining apps for compatibility are Onyx, Thunderbird, SuperDuper!, and Tech Tool Pro. As stated above, Onyx the other day released a version compatible with Big Sur, and there is a second beta of Thunderbird that has showed a lot of promise (although I am using the current non-beta version of it while testing V11.1 of Big Sur, and except for one very, very minor glitch, it's working fine).
Given that there is nothing earth shattering in Big Sur that would compel me to move to it now (same was true for at least the last 5 or 6versions of the Mac OS), and with it always being the case that the first 2 or 3 non-beta releases contain bugs (someone who is on the beta release cycle has already been notified of a V11.2 starting to be developed), it does not bother me at all. In fact, I suspect I will not make the permanent move until late January or February, as that is when, most likely, Tech Tool Pro will have a compatible versions (I assume SuperDuper! will already be compatible by then). That would mean that by that time, V11.2, or possibly V11.3, of Big Sur will be available. Meanwhile, I am perfectly fine with using the latest version of Catalina until then. I will also continue to test Big Sur on my external SSD until then. IN fact, except for one or two daily tasks, and 3 weekly ones, I will be using Big Sur just about all the time (like now).