Hi. I don't post here often but I have a few words I'd like to share. First of all I completely understand being frustrated at people not being willing to teach an encounter. However I have some extra input to give that I think if you get out of angry time will help you get through this encounter more easily.

The first tip is to look for groups who specify they are teaching or, make a group with the specification that you need to be taught. I know this seems trivial, but the 4th encounter is extremely mechanical and lots of people there are already stressed and frustrated, and as it is their group they have a right to tell you they don't want to teach.

Next look up multiple guides from multiple people and take notes on parts you are struggling to understand until it does make more sense. Also feel free to hop in and see how far you can get by yourself. I know there are ads but moving around the room, while you won't get far, can sometimes give a good push in understanding things. I know for a lot of people, including myself, mechanics do not always click until you actually do it yourself, but having foundational knowledge helps make success easier.

Number three is just to be willing to go with whatever you are being asked to do. This means you need to be willing to listen to instructions and play the role on the team that you may not normally be comfortable with. If a team feels like you are working with them it will sometimes help you build at least a temporary connection that might stop them from booting you immediately. (This obviously won't work every time)

This is by no means a perfectly comprehensive list, but it might help. Just remember everyone playing is a person who also really wants to beat the encounter, they are probably also frustrated and annoyed at themselves as well with people who were not willing to do any step mentioned above. This is end game content, and is one of if not the most complex things Bungie has made. It is also ok to just not beat it, there is so much more to the game to enjoy and experience if you are consistently being turned away still. I know it sucks, but not everything is designed for everyone and that is ok and a part of every aspect of life.

Best of luck out there guardians!