1) Maybe Chakotay was the Alpha Male onboard, 2takesfrakes, but that doesn't mean that he was the right choice and more still, with someone like Seven.
To be honest, I would have rather seen someone, besides being sensitive and patient, a male (or female*) more... cerebral (who won't hesitate to challenge her, not to convince her that she is wrong but of the existence of the other possibilities with their advantages and pros and cons and let her decide what was best).
I'd like to remain that Seven - like Janeway - has the Cartesian spirit of the scientists that she is, not only because of her Borgness but maybe, due to her family heritage and IF she had to end with someone, it could be with a male version of Janeway or a human version of The Doctor (with less ego!), (both) who helped her to grow up and to build her own personality, effort that Chakotay has never made. Besides, he never made any effort to see Seven beyond her Borgness!
* ST: Voyager was made in 90s, when TV still force hetero-sexual relationships (remember the horrified reactions form some Trekkies after the kiss exchanged between Dax/Leonara in s1 of DS9). I'm pretty sure that if the show was made now, Seven - who, initially, had to be lesbian - , B'Elena or even Janeway could be as well openly lesbian as bi-sexual and of course, heterosexual). Besides, in the new series of ST franchise, Discovery, it is planned to have an openly gay character among the senior officers.
2) Again, when I read interviews given by Robert Beltran & Jeri Ryan - after the end of Voyager in 2001 and until recently - about in particular about Chakotay/Seven's romance in Endgame, both recognized that it was a bad idea because, unexpected (how 2 characters whose physical exchanges were very limited in the past and strictly of professional order, could fall in love as quickly?!).
If there had been a continuation, through a 8th season or a TVmovie, or even a reboot, it seems obvious to me that or Chak & Seven would split up or even, that their relationship would haven't survived once Voyager brought in on Earth. Besides, authors of books and fanfictions often choosed this way to favor J/C or J/7 ... though I'm well aware that some authors of fanfictions continued with C/7 because, well, they ship them and it's ok ok for me.