i fucked with lakka a bit over the summer on a pi4, seemed nice but it’s literally just retroarch embedded with ssh (i think you need to ssh in to pair a bluetooth controller) and smb preconfigured so you can copy roms over the network
using mine presently for pihole, rtorrent and smb. not the most ‘robust’ setup with a little external hd but it works and i can just stream media to my firetv with kodi. using dietpi and it seems pretty good, think it’s using like 70mb ram on a cold boot