Yes, that is it, thank You CGGXANNX !
The “problem” was Fasttrack, or better to say lack of it, I enabled Fasttrack, and now I get the full speed that ISP provides me.
btw, my connection don’t use PPPoE, but DHCP.
Now, I get my “dream” setup, where optical cable is connected directly to my MikroTik, the simplest setup without any media converter, and bunch of ISP devices, and ISP can’t control my devices.
Again, thank You very much !