It depends on what you classify as 'pay to win'.
Paying undeniably provides an advantage, but it doesn't make you automatically win. Skilled players can oftentimes outperform donators. Also, some game modes are more 'pay to win' than others, so that should be kept in mind. Minigames have barely any 'pay to win' advantages (apart from kits and coin multipliers in SkyWars) while ranks matter a lot more on, for example, OP Prison and OP SkyBlock.
In conclusion, it's all about perspective.