The most effective phone calls take less than a minute: say your name, your city or ZIP code, and what you support/oppose, maybe a sentence on why. You’ll be marked down on a spread sheet that is discussed at the daily office strategy meeting.
Other actions like brief emails, meeting in-person at the district office, meeting in-person at the DC office, can also be effective, but take more time and energy. Emails aren’t always read right away like a phone call must be answered for example. And you generally need to make an appointment for an in-person meeting.
I think the lack of correlation between public opinion and government policy is more than satisfactory to demonstrate how much our federal legislators care about your phone calls, yes.
I hear you and acknowledge it is frustrating. But your assumption seems to be that your view is shared by all and thus “public opinion” aligns perfectly with what you believe or at least that a majority agrees with you. We all do this because we imagine our opinions to be sensible and hey, why wouldn’t other people share them? But they don’t.