"I'll go in reverse. As bad as Su57 might be, as long as it can handle so called Chini 5th gen, it would do its job."
No, it can't. Russians are still in the era of dog fights prioritizing making highly maneuverable fighter aircrafts rather than giving preference to BVR engagements with sensor fusion and sophisticated network warfare combining all the resources of air force like other fighter aircrafts and AWACS.
"Chini equipment is in US and western material as well. There's no escaping that."
Western aircrafts might contain raw materials like Titanium and rare earth elements from China but never a finished product. Don't make wild claims.
"Delivery timelines delay is something you have to live with. You are talking as if HAL doesn't delay."
So, what is the point of going for Su-57? If there is a delay on our side at the very least it will be delivered and we will be in control of the product and we would have created a new industry within the country and strategic autonomy.
"What's the realistic AMCA timeline? What happens if the government changes?"
No one can say what is the realistic timeline. But there is no going back to the days of importing massive number of fighter aircrafts regardless of who is in power.
Chini jets have no demonstrated capabilities. It's merely a 5th gen on papaer.
US military is concerned about Chini components.

Lack of Chinese components threatens U.S. military readiness
In an age where technological superiority is paramount, the alarming dependency of the U.S. Army on Chinese components is becoming increasingly apparent.

Delays can occur anywhere. The point is that's not unique to Russia.
AMCA depends on continued support from the government which can change.
I too wish we didn't have to import jets. But we don't have the capability to produce 5th gen in the next decade. So we need a stop gap.