This: https://www.aliexpress.com/item/1005005477244565.html
I got the 2GB version and it’s quite responsive, I didn’t feel like I needed a faster one or more RAM, since I was only planning to install Neutron and maybe a few other players or some EQ app, and a better launcher.
Supports 64GB SD card, not sure if it goes higher but it already fits all the music I need (I use MP4/AAC, not FLAC). And most importantly it can power dongles via USB-C - I specifically picked a model that said “supports OTG function” and looked for the largest capacity battery possible that didn’t make the phone too large. Autonomy is quite respectable once you disable the bloatware and turn the brightness as low as possible while still readable.