Every now and then I’ll splurge and put in a tank of ethanol free fuel. I’ve found that by running WFO for 1/4-1/2 mile once every other week I’ve never had a carbon build up issue.
On my 3.5 ecoboost F150 I did a BG induction cleaning service and 44k additive at around 90k miles. Couldn’t tell any difference in power or mileage. I just assume there was no substantial amount of carbon build up to be cleaned out.