I visited Russia solo last year. I didn't know any Russian (nor any languages of the neighbouring countries), not even basic words, apart from the few picked up in the research needed (e.g. автобус), but I can read the alphabet.
I brought a phone, a local SIM card, installed offline translations into the phone, and a detailed day-by-day itinerary with all the addresses in local language and also the buses to take, and searched the bus timetables beforehand (this was the hardest part).
I mainly visited museums and beaches on the trip. However, all the narrations in museums were in Russian only do I could only very limited part of them without knowing any Russian. I also visited a national park as well. These didn't require much language so I generally went well.
When I entered a food court in a shopping mall, I typed the words on the menu into the translator app.
It was essential to know how to read the place name when taking a rural bus, because we need to buy ticket from the conductor.
My trip generally went well, but on the very last day I was in trouble, even I had a local friend nearby. I went to a bus stop well ahead of schedule for a bus to the hostel I was staying, but the bus didn't show up. It was the last bus of the day in the direction I needed. I was in a rural area with a café nearby. I tried to ask if anyone saw the bus gone, but no one could understand. I also called the bus company but they didn't understand either. I showed my bus ticket and they started to understand my situation.
The hostel was only 12 km from the place I was at, however, the phone number was a long distance number which I couldn't call. I also had a local friend who spoke English well, but the phone number was also a long distance number. I tried to WhatsApp and Viber the hostel and my friend but the data reception there was very poor, so we could only communicate occasionally.
After the villager knew my situation, he offered me a ride in the direction I needed, but he couldn't ride me directly to my destination because he didn't have the paper needed to cross the border. He then dropped me off at the boundary of the frontier closed area and explained in local language to the guard about my situation, lucky the guard spoke a little English, calmed me down and helped me to get someone to ride me across the border to my destination.
The border I needed to cross is inside a national park and most tourists cycle through the border. It does not allow crossing on foot, but only on a vehicle. There are only 2 buses per day going thru, and all the information and trip reports I can find are about taking the bus between the cities, however I was trying to take the bus at the stop just before the border after visiting half of the national park (most tourists use a car or a bike to visit), and alight just after the border.
To conclude, if you don't know Russian you may still be fine, but you will be in real trouble if you are stuck in some rural area and the bus which brings you out of Russia doesn't come on time.