It is not about revenue. They are basically state corporation.

Search/ads and ride/delivery services. As you may know Yandex has very advanced SDC system which was used(SDC robots) by Grubhub in Arizona University. They have delivery services in London/Paris and taxi services in Insrael and couple European countries.

As for the Russia I found news(in Russian) that McDonalds was huge part of orders in delivery service. Ads system fully broken because of Google suspension. Without concurents average prices will rise exponentially. Small business will not be able to buy ads and will closed in near feature.