You can buy the Fairphone 6 with /e/os preinstalled (directly from Fairphone), it costs more and the additional cost goes to the devs. Also they have their own optional paid private cloud services (it’s basically just a managed Nextcloud instance). Others like iodeOS sell various phones with iodeOS preinstalled at a markup and they have a subscription to unlock additional features (their software is fully open source and it still offers a complete experience without them).