Yeah, Russia is one of the world's biggest oil producers, but we are only talking about a few million barrels a day exported. And most of that circumvents the G7. If Russia were to give the G7 the discount then other importers would require the same.

https://www.statista.com/statistics/1302241/russia-crude-oil-export-volume-by-country/#:~:text=Published
by Statista Research Department, Apr 20, 2022,approximately 640 thousand barrels daily, followed by Germany.