USB MIDI and DIN Midi are not connected in the RYTM (or other Elektrons) - so you can’t pipe info from USB (computer) to DIN(out on AR), not as an interface is designed to
somebody hacked something up with a DT and maybe PD, I can’t recall, but essentially it’s not a MIDI interface, it’s only capable of sending USB midi to itself, not onwards via DIN
If you look for an audio interface then you’d need to look into all the variables there, pretty much anything you’d find available will serve your basic needs, it’s a question of deciding how many ins and outs simultaneously and so on, whether the microphone preamps are an issue or not for your use cases and things like the monitoring and routing options, unbalanced/balanced etc - they’re all kinda in a similar ballpark with plusses and minuses
I am tickled by maybe getting the Tascam 2x2HR for a small scale way to get nice audio in out of a Mac and midi in a tidy package with good preamps compared to rival products - there’s a cheaper Behringer offering (204HD iirc) but I don’t know about their driver support for windows etc - then you go up to things like the MOTU M2 M4 which are going to be working well for a long time - there’s so many factors to think about but if it’s for occasional use and convenience perhaps you can cut down on feature requirements, but then you may have committed that one feature you later learn would have been handy - reading product reviews, especially on Sound On Sound will give you an insight into the benefits of some things that may appear inconsequential - if it were me I’d do research on the budget end and see if you can get by with any perceived issues discussed online, this is very well specified and covers lots of bases and comes at a good price
At the upper mid range you have these, more than twice the price for less features
https://www.soundonsound.com/reviews/motu-m4-m2
If you want to keep things simple and just add MIDI then a thing like this is a simple option, just don’t go too cheap with one of these types … the $5 ebay unbranded ones would not be worth it imho a people frequently report these choking or dropping info