Scott I am new to the Android custom ROM scene
Small clarification : the term ROM is wrong, but many users are used to using it, there is no such thing as custom ROM.
Scott I didn't know that mobile hardware is more secure
Well it depends, AOSP is a secure and privacy-friendly platform, but the code can always be modified to make it invasive and breakable, Google takes its platform seriously, third-party OEMs don't really use Android but broken versions of it that don't even respect the minimum standard in terms of security and privacy, for the hardware either. Android isn't really an operating system but a family and its dispersed nature causes it problems.
Since the Edward Snowden revelations, a new business has sprung up around the sale of privacy-enhancing smartphones. It's a scam, or worse in 99% of cases, because that's how this industry works.
Scott I thought mobile phones were toys and wallet gardens for Tinder, Netflix and co.
From what I've observed, this is pretty much the way many users use their smartphones.