> If your phone is not supported by GOS, you should look carefully and compare between /e/OS and Stock Android.

If you have an iPhone that's still supported, you have strong privacy and security. If you have a phone that's not an iPhone and not supported by GrapheneOS then you likely have a phone with atrocious privacy and security regardless of OS choice. If people can afford to get a secure device with years of proper support remaining then they should do that rather than using an insecure device with a sidegrade for privacy and security using a problematic AOSP fork. LineageOS is far less problematic than /e/. If people want to switch the OS to something else due to the OEM abandoning it or to avoid Google Mobile Services they should use at least use LineageOS which is less of a privacy and security downgrade from OS. LineageOS does not fully maintain the privacy and security of AOSP or fully keep up with updates but it's a lot less bad than /e/. Most alternate OSes are forks of LineageOS to reuse their work on hardware support and nearly entirely make privacy and security worse, not better, so why not use the upstream project instead?

> I had a Fairphone 3, and after 5 years, /e/OS was outdated by 4 years w.r.t. the manufacturer updates. In other words, Stock Android coming from Fairphone was more secure than /e/OS on that Fairphone.

It's important to note that an alternate OS depends on the OEM for firmware and in practice much more than that including kernel and driver updates. It's theoretically possible to replace the kernel and drivers with much different ones but it's not done in practice by alternate AOSP-based operating systems. If the device is abandoned by the OEM then you aren't going to have a secure device.

/e/ lags far behind on standard privacy and security updates everywhere but misleads users with an inaccurate Android security patch level along with many inaccurate privacy and security claims. LineageOS is much better than the fork of it by /e/ and does much less to mislead users, although it still has the inaccurate Android security patch level and many people still wrongly believe they're getting patches they aren't after the OEM dropped support.