It is a bit misleading, at least for Lithuania, but I believe for Estonia and Latvia too.
First of all Baltic states does not import electricity from Russia/Belarus anyway, for the last 4 years, regardless we are still synchronized with them. So synchronizing would not affect energy price (to be precise it will affect, but it is fraction of euro cent so it is very minor).
Other thing is that electricity is in open market, so you can get individual fixed price per individual provider, or you can go for market price changing by hour, if there is technical capacity (smart meter installed).