Which is better, chocolate ice cream or vanilla ice cream?
No one can give you an objective and unique question, because PVP and PVE are not comparable values, they are different approaches, one focuses on making people compete against each other. The other, in making them cooperate.
As they are different approaches, some people enjoy one more than the other, in the same way that some people prefer vanilla while others prefer chocolate. The decision you make will attract one type of people or another type.
But neither decision is absolutely better than the other.
Personally, I think that PVP is much more complex to manage as a developer, because people who cheat can ruin the experience for the entire community and lead to the game failing.
On the other hand, in PVE, you can always implement private servers, so that a group of friends can play with each other and thus avoid people who cheat, something that does not work on a PVP-focused server.
What I do recommend is that you read a little, analyze how MMOs work, there is a lot of information floating around on the internet that could be useful to you.
By the way, I don't know what you are basing it on to say that 90% of games have online support, it seems like an exaggeration to me.
Of the 970,000 games indexed on Itch, only 18,000 have multiplayer, that is, 2%
On Steam, of about 100,000 titles, only 16,000 appear under multiplayer.
Many games have local coop and use tools like steam remote play or parsec. So really the number of games that natively support an online game are less.