The entire idea of taking over Ukraine is to steal its resources and they would become a net exporter with a fairly small upfront investment. If Russia controlled Ukraine, they would control ~30% of the World's fertilizer distribution, tons of grain, and would give them a stronger foothold on natural gas distribution and oil reserves, all while being on Poland's doorstep. Putin is a Eurasianist, he doesn't care about the people in Eastern Ukraine.

https://hir.harvard.edu/ukraine-energy-reserves/

https://www.cbc.ca/news/politics/natural-resources-ukraine-w...

https://www.cnbc.com/2022/04/06/a-fertilizer-shortage-worsen...

https://en.wikipedia.org/wiki/Natural_gas_transmission_syste...