No way to completely secure phones?

Hello, I'm new to this and have a bunch of questions, I read the wiki and it says that phones are never secure because of RTOS but I was wondering if this is still the case since the wiki is a bit outdated? Is there any phone out there with an open RTOS? How about those open source phones like Pine/Librem? Also, privacyguides.org doesn't mention RTOS at all and recommends Google pixel phones for privacy, like a Google product of …

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