I see it totally normal that Mudryk didn't perform very impressively this season. Because the whole squad of Chelsea were very inadequate. Their morale was so low that they even gave up on the season quite early. In this situation it wouldn't be a healthy assessment about a player. There is a new period starting for Chelsea now with Pochettino. This is going to be the most important time period to watch Mudryk's capabilities. If the team make a good start the expectation from him will also be high.
If he still can't impress people then I will also agree with the people who think he isn't good enough for Chelsea.
On the whole, I agree with you to a certain extent. You can't win a team game alone, in this case showing well. He might not justify the 100 million he was bought for, but he should definitely fit into the squad. His goalscoring form last season was poor and I don't expect it to improve, but he could be a new prodigy if Chelsea start showing well in the new season