Being able to clear solo duties shows that you yourself are able to meaningfully contribute. I’m not directing this directly at your friend but just in general this game hides how poorly people perform. If you are playing a WHM and kinda just face rolling your keyboard and the WAR is doing 90% of their own self healing you can feel like you are “contributing” when really you are just kinda there. Same as if they were a DPS. How are they aware they are meaningfully contributing? It’s very easy to feel like you are doing your rotation semi correctly only to be told that you are being out DPS’ed by the healer.
If you feel like you are meaningfully contributing in a group setting but are getting walled by solo duties there is a good chance the game is simply hiding your lack of contribution. There needs to be checks every now and then that YOU are reaching the adequate competence level, not that collective group is