CodexAG So all my effort to get a Grapheneos phone will be for naught if I download normal apps like uber, twitter, tgram, Whatsapp and meta?
No (see GrapheneOS).
I want to be able to use these while still having at least some layers of protection from these apps themselves...
If you are concerned that a maliciously-formatted message might exploit a vulnerability in a messaging app and allow a third party to extract your message traffic from that app, various GrapheneOS hardening methods will reduce the likelihood of that scenario (most reduction at present on Pixel 8 hardware).
If you are concerned that a malicious app might break into Play Services and use Play Services's privileges to extract information from your device, it's great that on GrapheneOS Play Services is not privileged. However, given the catastrophic legal and regulatory implications, it seems unlikely that a mainstream app would do anything like that.
If you are concerned that a ride-hailing app might compute a list of people who get picked up outside bars four or more nights per week, and sell that information to alcohol-abuse counseling services, GrapheneOS can't help with that, because no OS can. Providing sensitive information about yourself to an app with network access means the sensitive information may well be available to the app authors.
GrapheneOS definitely provides "some layers of protection". It cannot in general convert nasty apps into nice apps (no OS can).
If one has committed to running Uber and WhatsApp on some phone, GrapheneOS is a great OS for reducing downstream risks. GrapheneOS does not make those apps, or any apps, free of risk, especially not privacy risks related to potental misuse of usage data.