Selfhosted

So background, my kid has seizures often. He is currently on 5 different medications to try to control it(plus 1 for sleeping and 1 for his liver enzymes) plus severe non verbal autism so he can't tell us if he already had his meds. Currently when it's medication time, it's always "did you give him his meds yet?" and we have no way of tracking how many seizures he actually has besides "alot more recently" or "it's gone down recently". Yes he had multiple doctors and this is NOT a post looking for health advice.

I am creating an app for phones(c# Maui) which will send json objects to a api to store/retrieve data in a database(when he last had medication x, when he has a seizure etc). It will probably only be used with in my family, maybe 20 entries a day on a really bad day(7 medications twice daily + 6 seizures to give a round number) but should be less then 10 transactions(most medications given at same time).

What's the cheapest/easiest was I can host something like this? I do not have a static ip. Yes it's health information but I'm only storing first names and tracking time of events, not too worried about hippa like security.