Your definition of imperialism is taken from an imperialist source, interested in obfuscating it.

Here, some reading: https://arkansasworker.com/is-russia-imperialist/

And how the entire war came to be:

https://archive.ph/2ppei

https://www.moonofalabama.org/2023/02/the-buildup-to-war-in-ukraine-february-15-2022.html