There are more extensions for Edge C, in the MS Store, then there were. Someone here in the Forum was saying something about "Back to top"... there IS such a button offered in the MS Store. And for something similar to Add notes there is THIS.; it is worth a look.
NB: I grabbed the Top button and since sometimes I mouse around whilst maybe not hands on the K/B for a bit, I'm, actually, finding it quite handy & likable, a number of times; just having the option of having it there is cool. (Hey, <-- that could be just a Drew thing, of course). I'm, always keen to discover things & try them, even if temporary. If on keyboard there's, what?, 3 ways there, but, who's counting, eh?