If a country experiences stagnation regarding the economic growth of a country then it has a big impact on people's lives because there will be an imbalance that occurs. So that the public sector which is usually a step to support people's lives will have problems, such as food problems and so on. The state has a responsibility for the economic growth cycle and they have ranks to control the prices of goods in the market. What happens is that they do not side with the people and consider more the problems of companies and the problems of the country's economy.
Usually this happens because the government is corrupt and has no vision in managing the country and although in certain cases all countries experience the impact of inflation or recession at an uncalculated stage because certain problems occur. Economic growth is very important because it speaks of a wide scope and if there is no principle to control then the problem will arise bigger.
I would guess that you are right that stagnation would result with big companies keep taking money, while smaller investor or just regular people not growing with it, so all the big companies would take all the money. But when we are talking about stagnation, we should not just take it face value, we can't just say this is why it is bad, we should compare it to make sure that it is bad.
So, when you compare stagnation to inflation, which one seems worse to you? I would say a very very high inflation could be much worse, of course a 5% inflation would be fine, that is not too much, I think people can live with that, anything under is perfect, but what if you had like those famous 100%+ ones? Argentina had one, Zimbabwe certainly had a lot more, and Turkey recently had one I believe. Those are much worse than stagnation.