It took them only 18 months to add support for a single browser. That genuinely is amazing, but not for any reason that is good.
How long did it take Bitwarden to add Vivaldi support again? Oh yes, I think it was the same day that it was requested.
I'm genuinely happy for you that LastPass have finally got around to performing this colossal feat of engineering, but I'm also very glad that LastPass's inertia became my impetus to migrate to Bitwarden last year.
Not only is Bitwarden far better supported, but it also has far fewer bugs.
LastPass didn't resolve this issue, Vivaldi did, and with no help whatsoever from LastPass.
I moved to Bitwarden months ago because of this issue. And I wished I moved to Bitwarden a lot earlier. First, seriously Bitwarden is just a lot better than LastPass, second, if I moved earlier, instead of waiting for never coming support from LastPass, I could have used my default browser 'Vivaldi' without the useability hassle because of a lack of support from LastPass, to use MY credentials and passwords with my choice of default browser.
Plus moving from LastPass to Bitwarden was very easy and quick. Don't mess about with LastPass, they're useless.