A huge amount of apps that an average user needs are on the playstore and require the services.

Ad populus fallacy. Not all apps on the playstore use google services.

Google leverage that to force apps to use their pay services.

Google forces apps they distribute in their store to use their payment service to prevent their services from being used for free while a company makes tons of money using their platform. This is especially important on mobile where free games with micro-transactions are the norm.

Google is using an unrelated thing to force the use of their pay services. Hence monopoly.

Google is forcing the use of their services if you want to use their services, doesn't seem that absurd.

It doesn't matter if a tiny percentage don't do that. The vast majority need to.

It absolutely does matter, Google doesn't control anything outside of the play store, and they allow you to install things from outside the play store, so it's not a monopoly if people choose to use their store but could distribute their apps without it. That is like claiming Steam has a monopoly over PC and forcing them to allow people to sell games without paying steam for their infrastructure.