Sometimes having generic Linux capabilities on network equipment makes it hard to understand the configuration. On RouterOS you can just /export the configuration and read a single file. On Linux/SONiC there are multiple ways to do the same thing - you can do one part of configuration using ifupdown, then make some changes in systemd-networkd, a bunch of shell-script DHCP client hooks, rc.local, cron @reboot. Imagine being handed over a router that someone has fixed by doing some runtime reconfiguration (like `ip ro replace default via 192.168.0.1 advmss 1410`) that would vanish with almost no trace (except maybe .bash_histotry) when you reboot it - that won't be possible (without doing very special scheduler/script trickery) on RouterOS.

But if you still want it, MikroTik doesn't try too hard to prevent you from running modified software. You can port OpenWrt, and most modern MikroTik devices use modern enough Linux to use a device tree blob. Try pulling out a dtb from your firmware and ask an LLM to do the initial porting - just don't forget to backup your RouterOS license key first, they are device specific.