If your flash photos are blue, your white balance is off for the particular flash you have. Manufacturing variations in LEDs can cause the standard camera settings to be off. In the camera, choose “More…Pro Mode…White Balance.” Try using “Sunlight,” “Shade,” or “Cloudy” to make the pictures look warmer and less blue.
As for the focus, I don’t know what to tell you. My phone camera focuses almost as fast as my mirrorless camera everywhere except in low light shots. In indoor level lighting, it takes my phone about 2 seconds to gain focus while my dedicated camera focuses almost instantly. Outdoors, it’s hard to notice a difference at all between my phone and my dedicated camera.
As for your phone calls and texts issues, if it’s not issues with the carrier and if your messaging and phone apps are up to date, you may have a case for warranty replacement. First, I would check with the carrier and make sure the network settings and APN’s are all set correctly in the Android settings.
One other thing to check, the current version of the phone app from Google has a setting to look up the caller number through Google Assistant before passing it through. This is being sold as a method to filter Spam while still allowing “Google partner businesses” through. If you have the Google app and the Google Assistant app disabled, try opening the 3 dot menu in your phone app, then choose “Settings…Caller ID & Spam” and then disable these two features: “Filter spam calls” and “Verified Calls.” You should be able to leave “See caller and spam ID” enabled. If those other two are enabled when Google Assistant and the Google App are both disabled, you may get weird things happening. Those two “features” were added to the app in the last two months. As I still get potential spam calls marked as such (not blocked unless I add them to my block list), I see no advantage to adding Google as an intermediary between me and other callers.