Well... Have you taken a look at its datasheet?
The reason why it was not working before is just the swconfig driver does not (and can not perfectly) implement IGMP snooping.
The earlier version (kernel 5.12 or earlier) of MT7530 DSA driver just forwards all multicast traffic to the CPU, so it works like the swconfig with multiple VLANs. The current mainline version programs MT7530's FDB to filter multicast traffic so the CPU won't have to forward them, but even then the IGMP snooping in hardware is not actually used.