Best ways to approach smooth terrain erosion

Hello, I am making a 2D game in which I intent to have a big emphasis in smooth terrain and its respective destruction. I want this game to have the best feeling possible to the players.

In order to acheive this, I thought of eroding the terrain in the client side of the player that shoots the projectile that is responsible for the erosion, then doing so in the server side. This, however, causes some weird behavior, where the terrain tweaks a little, as you may see in the video below.

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Any recommendations for what I should do regarding terrain erosion?