Bottas proved he could be just as fast as Hamilton, winning 10 races for Mercedes, but he was also never encouraged to challenge, unlike Rosberg, as they didn't want another uncomfortable situation like in 2015-16.
After that Hamilton had no challengers; Bottas was pushed to 'second driver' status, Max and Red Bull were nowhere near, Vettel pushed with Ferrari in 2017 but they soon fell by the wayside and overall those years were just dull. 2018 to 2020 were practically pointless as nobody was catching Mercedes (2019 particularly).
Now nobody is catching Verstappen, so titles 2,3 and most likely his 4th are practically gimme's, just like Hamilton's 5,6 and 7.