It's clunky af.

Compare Retroarch to AetherSX2 if you're on android - Aether is not nearly as fully developed as RA but from a user-interface perspective Aether blows RA out of the water.

There's a noticeable absence of sub-sub-sub menus and the vague menu naming convention that RA uses (why anyone would think that menu names like Interface, Display, Controls, Input and Configuration are a good idea is completely beyond me. Those are all so broad and ill-defined that the setting you're probably looking for could fit into at least half of those top-level menus. Conversely, you also have Directory, Playlists, File Browser, and Saving which are all top-level menus in RA that could easily be put into one menu named something like File Management.) Aether also provides a screenshot of each save state and the date/time it was modified which is a huge quality of life feature imo.

I'm a big fan of two-tier menu organisation when it comes to any kind of software: it should always be that the main menu options that every user needs are front and centre while the nitty gritty and poweruser options that are generally not used, not needed, and have the potential to break things should be tucked away behind a kitchen sink sub-menu with a name like Advanced Settings so if you have the want or need to tinker you're able to but you don't have unnecessary menu options cluttering up the interface.

Just look at the Input menu on RA - there are so many poweruser options at the top of the menu and the descriptions are vague and recursive "Override the input binds with the remapped binds set for the current core". What?? Mate, all I want to do is to map the buttons so I can play the game smh.

Honestly I think the only app on Android I've come across whose settings menu is more of a disaster is Podcast Addict, where there are like 4-5 different entry points into settings that are scattered across the app (gear icon, triple dot menu > App settings, Podcast episode description page > Customize menu with another gear icon, Player triple dot menu > Settings (player)) and different entry points provide different settings options. This might have changed since last I tinkered with the app but it was such a clusterfuck that I get flashbacks any time I even think about trying to change the settings in Podcast Addict so I haven't looked recently.