Plenty of western experts have discussed this very issue for many decades now. It's rather concerning that you're entirely unaware of that.

• https://truthout.org/articles/us-approach-to-ukraine-and-russia-has-left-the-domain-of-rational-discourse/
• https://truthout.org/articles/noam-chomsky-us-military-escalation-against-russia-would-have-no-victors/

50 prominent foreign policy experts (former senators, military officers, diplomats, etc.) sent an open letter to Clinton outlining their opposition to NATO expansion back in 1997:

George Kennan, arguably America's greatest ever foreign policy strategist, the architect of the U.S. cold war strategy warned that NATO expansion was a "tragic mistake" that ought to ultimately provoke a "bad reaction from Russia" back in 1998.

Jack F. Matlock Jr., US Ambassador to the Soviet Union from 1987-1991, warning in 1997 that NATO expansion was "the most profound strategic blunder, [encouraging] a chain of events that could produce the most serious security threat [...] since the Soviet Union collapsed"

Even Gorbachev warned about this.