Russia has no easy way to transport oil to markets in China and India. The vast majority of oil exports travel via pipeline over land. In case you haven’t been paying attention all of the geopolitical hot spots over the last few decades have been over determining where those pipelines are going to run.
In fact it just so happens the land taken in Ukraine by Russia is exactly where the oil is.
The west thought it could control oil tankers by denying maritime insurance which is also having an effect on the movement of Russian oil.
Yes, the insurance issue is a problem for them, but they may try to self insure.
Great 14 minute vid on this issue with What’s going on with Shipping: https://www.youtube.com/watch?v=p_u90eYyW04
So the west can tell all countries to not sell maritime insurance?