I think the bookmarks could be placed in the "More" menu and in the avatar menu.

Thank you for reminding me - it had slipped my mind. I agree with your thoughts, aligning the functionality with the idea of "Subscriptions / Communities", it would make sense for Bookmarks to live alongside Subscriptions.

In this respect, you could dispense with the text only if you use correspondingly effective icons. Otherwise, the text is rather helpful.

I agree. If an icon is instantly recognisable, like your example, then the user doesn't have to think because it's known to them (so the rule still works 😉) - it also applies to text where (especially) in finance, jargon is used and the user will often ask "what does that mean??"

It's tricky to get the best balance of removing elements and ease of understanding. The good thing is that removing the text or icon is an extremely simple change that could be done in either the JSX or CSS file - the elements are in the HTML and CSS is currently used to show/hide them.