Russia, as a country, does not trust many foreign institutions already - at least the western ones. They’re considered unfriendly, undesirable, and dangerous.
At the same time, Russia, as a country, is comprised of many people, including the ones that either directly represent its government in the form of deputies, ministers, and many other official figures, or use the wealth they’ve built in Russia through schemes and theft and murder and other crimes to build their stashes in democratic countries that have strong institutions and slow bureaucracies to protect their assets.
Most of these people have mastered doublethink, being able to switch their work and private personalities with ease: Get to the government office and pretend you absolutely hate everything to the west of Russia’s borders (except Belarus, maybe), including their values, happily vote for laws opposing or hurting them (mostly because you were told to “from above”), make anti-western speeches and so on and so forth - but once you clock out, you check on your kids in London, check on your French business, check on your real estate in Spain.
They live very double-agent type of lives, and will keep living them that way. None of the people in power have any incentive to make Russia a self-sufficient country in any metric, because that’s not what they wanted to be in power for, not even close - so Russia will always be interested in foreign institutions and markets and investment, because isolation is definitely not in its interest, nor is it appealing to anyone in power.