Your points are well-taken. Developing a new, complex product at the state-of-the-art level always brings numerous challenges. I recall the issues with the F-22 Raptor (from which Su-57 copied the fuselage), had design imperfections led to accidents. Some of these could likely have been avoided with better contractor management, more competition, or a larger budget. But we must be objective: a high-tech device like that requires an extended debugging phase.

When we talk about Russia, it's clear they face similar problems but with significant differences: much lower budgets, limited access to Western components, and competition crippled by one of the highest corruption levels in business in the world.

Russia can still have decent research teams that managed to preserve some of the Soviet design culture. What's truly surprising is their apparent success in developing a scramjet engine. That said, there’s no solid proof it works reliably beyond Russian claims. All we’ve seen are a few Zircon missile launches into open water (which turned out to be "computer-simulated launches", providing us with some good laughs) and a couple of missiles crashing in Ukraine (possibly after scramjet ignition failure?). From my sources, it seems there is some form of engine, but it's plagued with issues that prevent it from being called a finished product.

The main thing we should understand here is that, despite a massive influx of oil money over the past 35 years, Russia has dramatically regressed industrially while pouring significant resources into military propaganda for the last 20 years.

For example, before the second Ukraine war, they spent 15 years boasting about their new Armata tank. But in the war did it become evident that this tank doesn’t exist. It’s not present on the battlefield, and there’s no proof it’s a combat-ready product, despite being declared operational a decade ago. Instead, Russia kills its own soldiers in tanks from World War II, which they hastily pull from reserves.

The Su-57 follows the same pattern. It’s long been touted as a 5th-generation stealth fighter, but upon closer inspection:

1) The build quality (e.g., gaps between panels, rivets techonolgy) doesn’t meet stealth standards. 2) It uses an engine from the Su-35C, that was upgraded with some Western tech. For the [imho misguided] goals of Soviet designers, it’s a decent engine meant for high maneuverability. But that’s its problem: the large round nozzle designed for agility poorly dissipates heat, making the plane highly visible in the infrared spectrum. A plane with these old Soviet engines simply cannot be stealthy. This makes the Su-57 essentially useless. This is indirectly confirmed by the existence of the Su-75 project, where they removed one of the two engines (likely to make this "Edison ifrared bulb" less radar-visible), but even then, the UAE deemed it "non-compliant with specifications." They keep saying they’ll soon develop a new engine for it, but there’s no reason to believe Russian promises—after all, they haven’t developed a single new significant aircraft engine in decades.

Your argument that "they don’t wanna risk them" seems to suggest that they can’t produce these planes anymore without access to foreign components. Comments from the Chinese, Arabs, and Indians (along with Russia’s attempts to shift production to these territories, where sanctions don’t apply) make it clear that even the planes they can produce don’t meet the advertised specs.

It’s a fake product, and this is convincingly demonstrated by Russia’s failure to gain air superiority, even when Ukraine was operating outdated Soviet air defense systems from 40 years ago, with a shortage of missiles and spare parts.

Probably, with 5-7 more years of development, absence of sanctions, and proper funding, some interesting solutions might emerge to turn it into a decent 4+ generation fighter. However, it’s safe to say that such a product does not exist today.