You can render over the exp bead, but have to clean it before it sets.
What’s your issues with it ? Yes beads need changing but a pet from that looks goodTake this as constructive criticism and not a personal insult,
It looks a mess, you've used the wrong expansion joint for a start, it's not a thin coat bead, that's why your having to build it up.
is there a break behind the insulation. For it?
Whst are you doing with your plastic finishing float in the picture?
You can't tell how even you've got it from the pics but it needs to be perfectly flat to receive the top coat.
It's a minimum 3 man job to top coat that it's a big panel other wise your going to get caught out with it, with not keeping your wet edge.
I'm all for having a go at stuff, but in my opion tacking a job like that is short sighted.that's a big practice area, and dpr is £100 a pale, cocking it ups going to cost you.