Well no. If the annexation proceeds well for them, they can engage all of their military...instead of just paid mercenaries and volunteers.
Being a SMO meant they could not use the Russian military, unless they volunteered.
Things will now change dramatically. Belarus is preparing troops and we might see them from other CTSO members. It us after all a treaty for alliances.
This war could end in a few weeks after Russia is attacked. Erdogan thinks Russia will take off the gloves and wrap it up now.
https://www.youtube.com/watch?v=qskLuWb0GEM
Oh, no! The Ukrainians will be shaking in their boots! /sarcasm
Seriously: Belarus will not field even only a single brigade in Ukraine!
Lukashenko may be an evil and corrupt despot, but he's not Putin-level crazy.
Regards,