If you want to set ether 3, 4 and 5 to untagged vlan called "Alf" with ID 11, ether 6 to untablled vlan "Bob" (id 12), and ether 7 and 8 to a trunk of both Alf and Bob, you can do
1) Create a bridge for Alf, and a bridge for Bob
2) Assign IPs for them (assuming your mikrotik is the router), and maybe dhcp pools, server etc
3) add ether3, 4 and 5 as bridge ports for Alf, and ether6 for Bob
4) Create a vlan interface on ether7 for Alf with vlanid=11, add to bridge Alf
5) Create a vlan interface on ether8 for Alf with vlanid=11, add to bridge Alf
6) Create a vlan interface on ether7 for Bob with vlanid=21, add to bridge Bob
7) Create a vlan interface on ether8 for Bob with vlanid=21, add to bridge Bob
But the killer is there are two different recommended ways to do it depending on the hardware.
/interface bridge port
add bridge=_bridge interface=sfp-sfpplus1
add bridge=_bridge frame-types=admit-only-untagged-and-priority-tagged ingress-filtering=yes interface=sfp2 pvid=10
/interface bridge vlan
add bridge=_bridge tagged=sfp-sfpplus1,_bridge, untagged=sfp2 vlan-ids=10
Looking at the text config now it seems quite sensible, and isn't far from SwOS, Linux CLI, or switch chip datasheets. But I remember getting to that point in the WebUI being somewhat confusing, perhaps due to the alternative in-CPU way you described.
- you need to enable hardware offloading for it
- different models have different limits on number of hardware offloaded bridges
- if it's not hardware offloaded, you run all traffic through cpu and kill throughput
Mikrotik's SwOS is alright and has most of the options you'd expect from a switch, but is missing the ability to have a human readable text config. I've got a Netgear switch as well, and I'd label its obtuseness on par with RouterOS. At the end of the day it seems every network vendor has their own bespoke proprietary UI that you have to suffer through.
In general I'm much more at home with Linux's iproute2/bridge-utils/nft. What I really want is some low power switches that can run OpenFlow or the like so I can centralize all the config back to my Linux router. On a home network, most devices shouldn't be talking directly among themselves anyway!
Another thing I really want is for network switches to have an RGB LED on each port that can indicate what VLAN it's configured for.