I need to be connected to a Wi-Fi network when I'm out and about. I have a generous monthly mobile data plan, but it doesn't provide as much as 25 GB of data per day, which actually happened once when I was using Nostr on my phone during a trip.
Discussion
You could try only using this on mobile. Didn't try it, don't know how much is using, because i have an unlimited plan but might work better for you.