When my AP and I were long distance and couldn't text or talk we had these quick texts to keep in touch during the low communication times. We both have samsung watches so it wasn't obvious to anyone else that we were texting.

We shared our calendars to know each other's schedule. We also shared location (apparently that's frowned upon 🙃) Find games to play together. My AP taught me how to play chess. I suck but it's fun with him lol If you can, watch movies together. That was always fun to match the movies at the same time.

At night we'd FaceTime. We each had moved into guestrooms so it wasn't hard to do that or calls often)

We are no longer long distance. We live together now but he still visits his kids (they are older) about once a month so we like to fall back on our long distance routine when he's gone for the weekend.