I have noticed that many games do not appear on the observe list. For example, any time a top streamer is streaming and playing ranked, I cannot find their game in the observe list on aoe4, even when I filter for 1vs1 and check every single game. I suspect (but do not know for certain) that people who hide their match history also do not show up in the observe list. It is possible this is an active choice by developers rather than a bug, but if so I’m not sure its a great choice.