Of course I already tried to delete anything not needed, like assets and infos. Even without all these files, it takes (for me at least) 20 seconds to load RA, and 10 sec to launch any game (scummVM games at least). I'm not new to Retroarch, and I already knew these tricks. And, of course, I ALWAYS start with a fresh new config file.
The only trick that really worked great (for me) : using Rgui instead of ozone/xmb
It seems the size of the SD card is directly related to the loading times (RA/Games), because it works much faster on my 32GB card (same files/same config files, same games)...but it's really slow compared to Switch or 3DS (<1sec)
ps : if you remove info files, you can't make playlist anymore, as Retroarch will not let you use ANY core (except DosBox). Reason why I kept active cores info files (~10 files).
But playlists are not that good...will remove all info files
BTW, MIDI rendering is really bad, I never heard such low quality music on Indiana Jones and the fate of Atlantis
Nobody has any hint for the touchpad ?
EDIT : latest 1.9.0 nightly, only ONE core (scummVM), no assets, no info, no config file. Vanilla as hell !
From the black screen
after RPX loading from Homebrew Launcher (so RPX loading time is
excluded) to the (partially broken) Retroarch interface (because of missing assets) : 18 seconds and 27 milliseconds
Loading a (not that heavy) game (Day of the tentacle) : 8 seconds and 11 miliseconds
Interface changed to Rgui :
RA loading : 15s
Game loading : Mania Mansion : 2s / DOTT : 7sec