I have placed an accordion in the hamburger menu for on mobile. When I click on the accordion, the menu disappears, so I cannot then see the submenu. I think the menu is automatically triggered when you click on something, that the menu goes away.
Most likely this is not possible without some custom JS which we can not give support on.
As you already mention, we close the menu whenever we click a link inside of it.
A dev quickly tested excluding the accordion link (which prevented closing the menu), but it seems like the accordion does not work in the mobile menu either.
He kept the code change for the mobile menu closing issue, but you probably have to re-insert the accordion to make it work.