...the Eastern half of Ukraine has always been part of the Rus peoples territory...
“...the Eastern half of Ukraine has always been part of the Rus peoples territory...”
Not true at all.
The eastern part of what is now Ukraine was mostly Kazar. The Rus, and in particular the Kievan Rus were west and northwest of that area.
Then why did Russia sign away sovereignty and border rights to Ukraine in 1994?
The Rus peoples arose in the 9th centuries when the East Slavic tribes invited the Rurikids to rule over them and formed the Rus.
Prior to that, it was Khazar and prior to that, Iranic speaking Sarmatian and prior to that Iranic speaking Scythian territories. Not to mention parts that were East Germanic tribes, Greek city states, etc. etc.
And after the Rus coalesced, then most of the coastal areas were not Slavic but various TurkiC tribes
Not even in 1400 AD do we see "part of the Rus people's territory"
Your "always" seems to date from 1750 onwards