Multiple network parts bridge with VPN

Hi,
I need to connect multiple parts of the very same network located in different parts of the world through VPN.
Most examples I saw was about connecting two different networks through VPN. But the main goal is to have a possibility to easily move one location to another.
I have such solution based on OpenVPN server installed on Debian, and OpenVPN clients installed on several MT routers with bridge enabled on each one.
Mobility is working like a charm but during years of working like that, the configuration on the server became very messy. So we would like to migrate to Mikrotik-based-server, so configuration will always be easy to maintain/improve.
Unfortunately, RouterOS doesn’t support OpenVPN Server with UDP, so I need to find another solution. Can anyone advise something?

L2TP/IPSec maybe?

Hi,
Thanks for your reply, I already managed to configure L2TP/IPSec server. I just wanted to know if there is any other solution since OpenVPN server is not working in UDP mode.
Regards