Don't overthink it! I wait until a few of my indoor plants are just starting to look a little bit sad, then I water all of them. This has worked almost flawlessly for several years. No moisture meters, no additional nutrients, etc. Sometimes I feel like top watering, sometimes I feel like bottom watering. It's extremely low effort. One thing I have going for me is that I'm on rainwater, not city water. Use rainwater on your plants if you can, they love it.