Russia depends on Western oil tankers to ship its crude to the world. If Putin cuts production to retaliate against the G7 price cap, the West can lower the cap to make such production cuts super painful for Putin. Putin gets to decide how tight the noose around his neck will be.
Russia's current account surplus usually shrinks in the summer months when Western Europe doesn't need gas for heating. Indeed, from 2007 to 2021 the June current account averages exactly ZERO. However, this year the surplus is +$28.2 bn, a monster surplus of our own making...