I think nobody here really argued about who is the "better" heroine, or better games or whatever. The argument more is different. You see, books, movies and games are at the same time a commercial product and a work of culture. If HZD sold 20 million copies, it is undeniably a successful commercial product, I think nobody would say otherwise. If that means it has a big cultural impact though is too early to clearly say. Tomb Raider/Lara Croft had the time to access the situation, and Tomb Raider stayed relevant over more than two decades with influences on other works and releases in more media than one (movies besides the games). That shows that Lara Croft is a cultural icon. It is just too early to say the same about Aloy/Horizon. It just gets a second game soon and as far as I know has no other media reception. If that will have cultural impact we can talk about in ten years.
I suspect that the matter is very much one of a person's age at this point. People under the age of 25 today I would bet are more likely to be familiar with Aloy than with Lara Croft. Those are, statistically and historically speaking, the people who will still be gamers 10 and 15 years from now.
That's not to say Lara Croft has become less relevant by any means. On the contrary, all installments of the last decade's new Tomb Raider trilogy have bested the same franchise's previous sales record, which was set by Tomb Raider II from 1997, and this math suggests that Lara has indeed generationally expanded her audience beyond the traditional pool of 7 million or so long-term loyalists with this new trilogy. But for a new heroine-centric IP to best the top-selling Tomb Raider entry in fewer years on the market despite availability on fewer platforms is objectively a development of historic significance. That's the essential thing I'm noting here.