Christ wasn’t accused of not keeping the Sabbath, but breaking it.
There’s a difference.
In your estimation, you think it’s a small thing. Christ died because himself could not change the Law. And He made the Law.
In the view of the Pharisees, there was no difference between breaking and not keeping. The Sabbath had become more of a Day of Rules than a Day of Rest. It became a lot of work to rest on the seventh day. That was missing the point.
We are Saved by Grace which is “unmerited favor”. We cannot deserve anything.