“at one time in the past”

As did the Russians on the land of Ukraine.

17th and 18th Centuries

Parts of what is now Ukraine were incorporated into the Russian Empire, especially after the partitions of Poland in the late 18th century. However, other parts remained under Polish or Ottoman rule. The Russian Empire did exert considerable influence over these territories, often implementing Russification policies.

19th Century

Throughout the 19th century, the concept of a Ukrainian identity persisted, albeit under the umbrella of the Russian Empire for many regions. Some Ukrainians sought greater autonomy or even independence.

Early 20th Century and Soviet Period

After the Russian Revolution, Ukraine briefly declared independence but was soon incorporated into the Soviet Union as one of its constituent republics. While it was part of the USSR, Ukraine had its own Communist Party, constitution, and administrative structures, but Moscow held ultimate authority.

It wasn’t until 1991 that Ukraine was an independent country.

So is Russia allowed to take back the land they feel is theirs, and technically was, 30 years ago?

Meanwhile, “Israel” hadn’t existed since around 63 BCE when it fell under Roman control. It wasn’t until after WW1 and especially 1947 that Jewish people of the Zionist movement decided to reclaim their religious roots and move back to the area en masse.

So is Israel allowed to take back the land they feel is theirs, and technically was, 2086 years ago?