Why are new sanctions on Russia still being considered three years too late?

Three-and-a-half years after Russia invaded Ukraine, some western countries like the EU and Britain are vowing to impose strict new sanctions on Russia to "keep raising the pressure until Russia ends its war".

What I don't understand is how they are managing to find new pressure points three-and-a-half years after countries first started imposing sanctions. If they have sanctions they can easily impose on Russia, why didn't they do it three years ago, before a million plus casualties arose?

Maybe there is some clever strategy at work here, turning the screws very gradually for maximum effect or something like that. But, looking in from the outside, it just seems like Western nations have had perfectly good means of blocking Russia's ability to prosecute their illegal war that they have just not used. And if they have just found these means now, how many other avenues are there that have still not been pursued.

Is this just a case of keeping something in reserve so they can say, "Look at us, see what we're doing to help"? Are there compelling reasons why these forces have not been brought to bear before now? Does Canada have a whole list of potential sanctions that they are holding off on imposing? Hard to say.