PlayStore if you want to have it. Not everyone wants to have Google sniffing on your background just like Graphene with their “playservices”… Which is indeed Google with just a few options off. But people will never be able to get it pass their heads. Op is asking about open source… Not Google source
Main reason why I still use Silence app. Even though it hasn’t been updated in years, it has the option for muting notifications for each person. From 1, 2 hours, 1 day, 7 days or even a year. If anyone is interested here’s the F-Droid link to it https://f-droid.org/packages/org.smssecure.smssecure/