You have shared a lot of quality tips for long-term relationships. I have been in a long term relationship for 3 years now and I agree that communication is vital. No matter how busy we were, we often talk at least once a day. Its really challenging, but that helped us to keep each other in contact.

he would send me a specific Whatsapp Sticker, which meant that he needed space alone to regulate himself

This is cool. I would like to see how it works for me. Sometimes, we need our own space. Your idea about sending a silence sticker makes a lot of sense.