Check https://liveuamap.com/. It is a pro-Ukranian site so no bias. You tell me if most of Ukrainian coastlines are taken over by the Russians.

Donetsk, Luhansk, Kharkiv, Zaporiska, Kherson and Odessa traditionally have more Russian speaking Ukrainians.  See the blue parts of the map below.   So far Donetsk, Zaporiska and Luhansk are under Russia control.  The fight now is now at Kherson and Kharkiv.  Once Kherson is done, next is Odessa.