Is it possible to perform inter VLAN switching/bridging (wire speed) on single port with CRS3xx switches? I’m asking specifically about single port config because in such case simple VLAN stripping won’t do the job as switch doesn’t send packets back to the same port if it’s not in separate VLAN (MikroTik doesn’t seem to support hair-pin)
maybe switch rules can help??

I tried ‘naive’ way of switch rules aka force the same dst-port as source port without vlans and it didn’t work (switch didn’t reply to the same port) but hm… I didn’t try to do that with MAC vlans enabled. That could possibly work. I’ll try. Though MAC vlans itself are accomplished using switch rules so I sense possible difficulties.
maybe you are searching for VLAN translation feature,
in CRS 1xx and 2xx had available a lot of features related to that but that switches where too complicate to configure for people not accustomed to switching argot
i think in CRS 3xx mikrotik is taking a more simplistic approach, making configuration more easy to do at the expense of some loss in functionality in comparison with CRS 1xx 2xx, to make CRS line more friendly to a wide public non expert in switching
we’ll see if your situation can be solved today or maybe in future software releases, CRS 3xx is very recent and is being improved version after version