My understanding is that they have developed an import substitution plan for the jet and are resolved to keep producing it. [1] For instance, they are substituting the original SaM-146 engines with fully domestically produced PD-8 engines and I understand they are already, or close to testing the first prototype with the new engines (they already tested an earlier prototype with other import substitutions but which still had the old engines). [2]

[1] https://asiatimes.com/2023/09/russia-defies-sanctions-with-h...

[2] https://tass.com/economy/1699907

> or close to testing the first prototype with the new engines

Considering that Russian engineering culture is even worse than that of Boeing (and probably massively so) it’s unlikely that they can ever be competitive if that’s the main issue

Which begs the question, why didn't they use those engines initially? The answer is probably in their efficiency, because Russian engines are not known for that.