The ax² has no working hardware offload for bridge, but it has no problem with switching (same VLAN between its ports) at wire-speed. 2.4 Gbps throughput should be possible if you look at the Bridging (fast path) numbers that MikroTik published (even the 512-byte column). If you can use Fasttrack, then the inter-VLAN routing performance will also approach that value, because most of the packets will travel in fast path (the Routing none row).
So, while it might not have single digit CPU load when switching at wire-speed (1Gbps), switching including VLAN handling will probably not use more than half a core at 1 Gbps. The hAP ax² has a slightly better CPU than the older hAP ac², and here you can see real benchmark showing that non HW offloaded switching with VLAN at 1 Gbps only use 1/8th of the available CPU power of the hAP ac² at half of the possible CPU clock.