Ah sorry GBA games have like 5 different save types based on the flash used in them. Like EEPROM, SRAM, and FLASH. Usually that’d need to be configured in the emulator for the save type per game if it isn’t auto detected but I’m not aware of that being the case for DS. You could try a save state on one device and see if it loads on another.
Like the inclusion of USB 4 and HDMI 2.1. 4k120hz is nice but it’s too bad the deck can’t currently support that. Might buy one just to have for a future deck 2 support of the high refresh rate 4k.