more so

Which is correct:

[color=red]1) She was generous. More than anyone else I knew.
[color=darkblue]2) She was generous. More so than anyone else I knew.


Not pretending to sound too theoretical, just some notions relating ‘more\more so\ moreso’.

“‘More so’ strictly means ‘that to a greater degree’, and so recalls an adjective or adverb used earlier. Eg in the sentence, “Gina is studiuous, and Jon is more so”, ‘so’ recalls the adjective ‘studious’, and ‘so’ is a crucial element of the sentence while ‘more’ is not. We could change ‘more’ to ‘less\equally’, and the sentence would still make sense.
But ‘more so’ is used in several other ways, some of which are not strictly logical. “It’s not that Badet wasn’t happy for his peers. More so, he couldn’t understand why he was being overlooked” \Orlando Sentinel\ Here, ‘so’ doesn’t recall an earlier word, and ‘more’ and ‘so’ don’t perform separate functions. They work together as an adverbial phrase similar to ‘even more\ rather’.
Some writers unnessesary use ‘more so’ in place of the briefer ‘more’: Even moreso than E., D. has struggled to raise money early in his campaign.
’More so’ should always be spelled as two distinct words. It is also overused and misused. Wherever possible, stick with plain ‘more.’”

–To be on the safe side, I’d follow the advice, though 2) also sounds grammatical to me.

Both are possible and there is a very subtle shift in emphasis.