Is this something that's been happening for a while? Or just since the pandemic, people are struggling right now
Try reaching out to them, something could be up that you aren't aware of? The people you are friends with will grow and change throughout your life, peoples lives take different turns and we lose touch with people or decide that they aren't people you want to be friends with and that ok. But if you haven't already, reach out because any relationship (friend or romantic requires two people to put the effort in)