Thanks for mentioning R. For a bit of good news, current estimates are that most states/counties currently have R < 1,
https://covidestim.org. Hopefully we've passed the worst of Delta. I have no doubt vaccines helped, though I'm unsure how much. Obviously we didn't needed 100% vax rate to get to this point. Comparing with the situation a month ago obviously something else other than vax (and/or masks) has had a big hand in the R reduction (hint, natural immunity).
What I am pointing at is that there is a population vaccination level beyond which further vaccination has diminishing returns. There are fundamental principles like bodily autonomy and human dignity that we shouldn't throw away just to chase a slightly lower R number, cumulative deaths with covid, or any hyperfocused metric we use to track the pandemic evolution.
PS. I hold the underlying assumption that covid is endemic and over the next decade we'll keep having outbreaks until everybody builds up sufficient natural immunity.