Been there done that. Advertising is a problem most non technical users aren't aware of (as a problem) and often they're used to it, but if you install an adblocker, they indeed see that as a change, therefore "you and your damn adblocker" will get the blame for each and every problem.
In my opinion the only options are to either leave their browser as is or just installing Ublock Origin without telling.
Same... Used to have a Pi Hole on the entire network but had to remove it for this reason.
I have a Pi Hole as well and it's been pretty quiet in my house. I've had to whitelist a few sites (e.g., our kids' school gave out meeting links using tracking links in email that was blocked) but it's been pretty good. Definitely more upside than downside.