Is there a reminder/alert system for due or soon-to-be-due tasks?

http://noteapps.info

I actually had a lot of fun a couple years ago deploying PiHole on one of my RaspberryPi’s and routing all my household machines through it. It worked great UNTIL… my kid was turning in empty homework on Google Classroom and his teachers were getting up him about it. We chastised him thinking it was his fault until I finally discovered that Pihole was messing up his uploads to GC and literally causing this problem. I got super angry with it and walked away without even trying to troubleshoot. Had to profusely apologise not only to his teachers but to him.