I do not think Denis Manturov is particularly bad at his job. For example while he was in his post they developed Russian mass production of carbon fiber and adhesive, they made the wing all out of Russian components. The wing was certified with the PD-14 engine. And the PD-8 engine seems to be in an advanced state of development and ahead of schedule. It is already being flight tested. This is way better than the situation Russian civil aircraft engines were in in the 2000s. Where I think they did wrong was lack of investment in PD-14 serial production facilities. They should have built the factory so it would have been ready for manufacture once the engine was certified. Yet they have not even broken ground on it yet, and have to make it in single units in existing legacy production facilities which lack the capacity to produce it. Part of this I think was because a lot of the existing orders for MC-21 and SSJ were with Pratt & Whitney and PowerJets engines. They also had success in replacing consumables for the Superjet inside Russia which used to be imported like brake pads. Development of other Russian aircraft components was also talked about for years but the contracts to fund their development only began being issued like last year.
I think this is what Putin is referring to. They should be funding the industry so that the production facilities and personnel are in place so production can begin immediately after certification. Not wait for certification first, and then build the production facilities, and hire workers. It can easily take a year to fill a factory with tools, two years to build one, and it might take half a year or a full year before workers are trained properly.
If Manturov has issues, I think, is that he is big on procedure, and in crisis times like this you need to cut the red tape. He is also probably out of his depth as a technical leader or industrial expert. He used to be a sociologist before he went into public service. Still he has been working in the boards of aviation companies for almost decades at this point. Compared to the wreckers who were in before him, who consistently cut development of hardware inside Russia buying everything abroad, I think he is doing ok.