Do absolute R0 numbers have meaning without a specified environment? As in, shouldn't there be various values for R0 within a fully vaccinated community, R0 wi

Do absolute R0 numbers have meaning without a specified environment? As in, shouldn't there be various values for R0 within a fully vaccinated community, R0 within an age group, R0 relative to the prevalence of active infection in a community, etc.? I'm just wondering what complexity is concealed within an R0 figure. After all, if every infected person really infected 6 other people every 2 weeks or so, it would infect every person on Earth in about a year and a half. Which is probably why R0 is distinguished from R1. Since otherwise R1 would be R0**2, and I highly doubt it is. It could be higher if viral load was a large factor (you have x% chance of picking it up when around a single carrier, but >x% if surrounded by multiple). Far more likely, it would be lower as it burned out tightly-connected groups. Anyway, just thoughts triggered by seeing absolute R0 values.