I’m sorry to hear you’re experiencing this, I have a really similar situation and it’s really hurtful and difficult.
i find it feels like all of our day to day hard work gets unnoticed but I’m assured by a lot around me that as our children grow.. they do know all of the things we do.
you can only do what you can do and it sounds like you’re communicating with your children about your position. I try to plan my time (not aways possible) where my son has my total attention for our time together at specific points, so maybe immediately after nursery pick up we’ll do something he wants to do together. It might not be a materialistic thing but it’s time, effort and attention and that’s got to be worth so much for our little ones.
it’s hard, so hard I totally empathise x