The workloads (within each VLAN) can see each other - they just need a roundtrip to the router…
I think roundtrip-to-the-router would only work if you assigned a separate VLAN (and hence a separate subnet) to each container. Although MACVLAN apparently has 5 different modes of operation, one of which is bridging, and one of which supports inter-container layer 2 connectivity via “hairpinning” on an upstream switch. All very complicated.
I found Stéphane’s summary here: Macvlan vs network bridge - #2 by stgraber
It seems MACVLAN is faster, but relies on hardware support from the NIC, so the number of MACVLAN interfaces you can create is limited by your hardware.