I started using an app called aCar back when I used Android, then that app was purchased and the lifetime users were forced to subscribe. The name was changed to Fuelly and the new owner abandoned it 4+ years ago.
I have looked at a couple on iOS and they either are barely functional (only tracking fuel ups) or very extensive app permissions are used.
I am looking for something that will track multiple cars, ideally across multiple devices so my wife and daughter can track theirs too. Fuel, maintenance, part numbers, etc.
I used Car Maintenance Minder way, way back. It was perfect for me but it was also eventually abandoned.
Have a look at Simply Auto. I use it now. While it’s not as good as Car Maintenance Minder, I think it does what you’re looking for. I’m not sure about the multi device function though.
I know this is an old post but you may want to check out LubeLogger. It’s more a self hosted web app than anything iOS specific, but I’ve been using it for the last few months and like it a lot so far. I access my instance through tailscale, avoiding most of the security issues with making things publicly available.