Those two do look fairly average, only 900Mb and 500Mb.
Frankly assuming size == quality is a very disappointing way to think. And I found it inaccurate, for example my favorite one is Chateau Grand from soundfonts4u which is only about 250MB (note that the B must be uppercase, because lowercase means bits and it's a factor of 8 lower, as a physicists I have a pet peeve with people not using the units right 😆).
In any case, thanks for mentioning the other three sources, which I knew because they are are often mentioned, but other readers of this thread might not.
I second Sforzando. I greatly dislike Kontakt. There is also http://linuxsampler.org/downloads.html (which despite the name works for Mac and Windows too) which I find very intuitive interface (but it does not work with my sound card 😩 at least not yet), and https://sfz.tools/sfizz/downloads which I have not tried yet (hope to get to it today).
EDIT: rereading myself, I notice that this message sounds a bit rude on @burkey -- I apologize about that, it was not my intention (just saying my opinions: one should judge for the sound not the size, and try to use correct units, no bad feelings, only plain opinions) -- instead of changing the text I prefer to explicitly apologize for my poor choice of words. Thanks for your understanding!