Russia's answer to Starbucks, Shokoladnitca (in translation meaning something along the lines of "Chocolate Lover") features not only coffee, but meals cooked in their cafe-restaurants. As a popular nationwide franchise, there's plenty of seating an WiFi in every cafe. Their menus are always in both English and Russian (if you don't see English words in it, ask them for the English menu, or ask the waiters to translate/recommend something; plenty of staff speak English here). This particular cafe in Kazan has great staff, fresh food and quick service. In summer, they open up their patio outside, while in winter, it's warm and cozy indoors. This place is good because it's casual enough for a Digital Nomad to come in and spend 2 or 3 hours on their laptop without ordering more than one tea that's usually no more than USD$2-$3. After some hard work, you can visit the mall the cafe is situated in too, or simply walk outside to the main bus stop, or metro station.
If you don't feel like coffee, ask for the Sea Buckthorn Berry Tea - it's about 220 roubles and is really yummy!