Hello everyone,
I’m not sure how to better phrase the subject but i will try to provide better explanation.
I have rather complicated setup that i would like to make it work.
Consider following scenario, this is my in-home setup, so sorry for Serbian language on some terms but you should get the gist of it.

I would like to make MirkoTik route all traffic, because i will implement some advanced routing rules, VPN server/Client and more.
I want to keep local ip address subnet of 192.168.0.0/24 because controller.lan (and possibly some more devices in the future because this is where all the LAN Cables are) is connected to my ISP router (Technicolor). And that router also has wireless capabilities so it’s good to extend WiFi range by having two APs.
I’ve setup a bridge on MikroTik and joined all ports on bridge. Even ether1 which is direct connection to Technicolor.
I’ve assigned it IP as seen on diagram and I’ve setup DHCP server so it would assign gateway parameter as 192.168.0.3. Setup NAT masquerade on it and really everything works perfectly.
What I’ve noticed is that i have issues when i want to access controller.lan outside my LAN via port forwarding. Since technicolor is actually the gateway from which all traffic flows, I’ve setup port forwarding on it.
IF! I set default gateway on controller.lan to be 192.168.0.3 (mikrotik) i cannot access it due to MT masquerading outgoing IP and technicolor cannot track it. So I’ve added rule to NOT masquerade outgoing 22 (when response needs to be sent back to client) from controller.lan and all works well..
But I’m curious of other problems i might encounter. For example bridge loops, routing loops perhaps? How can i circumvent problems like those?
I realize that this is not recommended method but can anything be done to better utilize this type of setup since i would really like MT to handle connections and i can do so much more stuff to better utilize network equipment.
I cannot move MT in place of technicolor since i have coaxial cable going to it from which i get internet access.