The secret to get outstanding service on S7 is so simple!
Prior to flying
I had learnt basic Russian from YouTube "learn Russian while you sleep"
The moment flight attendants heard me speaking Russian, they were super friendly and attentive to my needs.
Food is good but don't expect fine cuisine .
The advantage of the business class cabin is the people you meet... such as a champion wrestler and a KHL's ice hockey star player !
Conclusion: learn a little Russian before you fly S7 and a new world will open to you !

I used to fly S7 regularly before covid and first time too it after COVID. They were decent airline with good quality, almost always on schedule. My flight was delayed by over 30 min without any announcement and nobody present at the gate to advise passengers how long to wait. Finally, they started onboarding everyone. Apparently, due to cost optimizations, they stopped using air conditioners when they onboard passengers. It was 35C on board when we entered and we were waiting for a take off for over 30 min in this mode. Stewardess was helpless in providing any information. The airplane was also like 30 years old with passenger seats condensed to maximum degree. It is more like a low cost airline experience those their pricing 2-3x times higher. Totally opting out from their service.

Very rude and unfriendly stuff. If they have a little opportunity to feel yourself uncomfortable, they would do it. Also if they have some informations to help you, they would never inform you. It would be better for them to take someone off the plane as to help. They also make some racist comments if you are not Russian. Well, I would not recommend this airline to anybody. There are enough options to choose and much more better services to the same price. Ok

Staff were not helpful at the check in desk. I am a musician and I had a very expensive professional guiter and they didn't allow me take it on the plane. I tried to explain that this is a music instrument in a soft case and it is impossible to have it with the checked in luggage. Even with the special buggage belt as you never know how they are going to handel it.

I asked them to put in the jacket cabinet or overhead in the business class but they insist saying that it doesn't fit and the flight is fully booked.

I was very late to the boarding and I didn't have the choice at the end but to leave them taking my guitar with the checked special luggage. When I got into the plane I discovered that the jacket cabinet was empty!! Furthermore, the overhead cabinets in the business class was empty too and could easily fit my guitar. I was the last one who got into the plane and still the cabin crew where very rude and refused to help me getting my instrument back and have with me on the flight.

It was very bad experience and never again!!

The airline its pretty good, overall experience was good and all things went as expected. S7 has really good airlines partners so good for people who have loyalty with other airlines and wish to take advantage while flying domestic in russia.