Doing multiple PSK / PPSK is not compatible with WPA3 (at least as supported by most APs today*, as WPA3 requires management frame encryption), so you limit to WPA2 only, therefore you're better off just having multiple SSIDs with WPA3 support. (Also that way you can have a "secure" network which is WPA3 Personal only, much easier than using WPA Enterprise and gives a reasonable level of security for home use.)
hostapd has supported multiple SAE passwords and identifiers since 2019; it even allows to bind a password to a specific MAC address and VLAN id.
Since most AP software is just hostapd wrapped up in some GUI, if they don't support these features it's probably just due to lazyness on the vendor part.
*: In theory password identifiers (https://www.gabriel.urdhr.fr/2022/06/07/impact-of-the-differ...) could be used with WPA3-SAE, but I don't know how good the support is currently...