For retail and services, how hard would it be for a native Russian company to take over from exiting firms? It's possible that I'm being naive, but it doesn't seem difficult as the staff and mid-level management are already trained to do their jobs. (This is already happening to McDonald's:
https://www.theguardian.com/business...d-rebrand-them).
Russia is mostly self-sufficient when it comes to food (
https://ihsmarkit.com/research-analy...ucceeding.html). It also has a high-tech sector that could potentially replace Amazon, cloud service providers, anti-virus software providers, etc.
OTOH, WRT the import of finished, high-tech products like assorted semiconductor technology... then yeah, Russia is in a difficult situation.
Luckily for Russia, the Geneva convention forbids sanctions on the export of vital medicine.