There’s a simple pause button on the web interface. I bookmarked it on my wife's phone and showed her how to disable and she's had no trouble since. At first she was skeptical about the pi-hole but after seeing the difference it made, she's totally on board. We don't need to disable it often though, maybe once every month or two.
Ha! At least once a week I tell the family "the wifi/internet will be wonky for a bit". Luckily we have unlimited LTE so my wife just switches to that until I'm done.
As a year+ long user, I attest to its greatness. Set it up on the cloud, set your router to distribute the dns and presto-blamo ad-free apps, internet and streaming.
Very occasionaly I might come across something not working. I could go to the pi-hole interface and whitelist, but I find it easier and so infrequent that I usually just turn off WiFi for a minute to load the page over cellular.