Like real "Heil Hitler" types, i would say there are very few. Its not 2007 anymore.
The most famous of them Tesak got his own cooking show on youtube now.
Fun fact i am partly jewish my self, and i know a jew when i see one, and this guy is a jew.
Then there are mor moderate guys. Like Div and Demushkin. This guys are one of those who actually care about Russia and Russians.
Since they sat with a jew Malcev and actually voted for his party they are disqualified from being called neo-nazis, although they are very right-wing.
Note being right wing is not allowed in Russia unless you are pro-putin.
Now pro-putin groups are the ones fighting in Donbass. Here we have all kindz of untermensch garbage like for example National Bolsheviks.
If i am not mistaking their leader sucked off a black guy and then wrote a chapter in his book describing how his cum tasted.
So to sum up: There are very few actual neo-nazis in Russia, but thousands of all kind of nationalists that are very divided on all issues. Since these groups are not really official anymore (except the N. Bolsheviks) any modern statistic on how many they actually are would be false since its simply no way of knowing.
Statistics from 2007 are most likely accurate thought since back then they had parties with membership, so they would be easy to count. Now parties are banned, and organizations themselves had some ideological changes that imo disqualifies them from being labeled as neo-nazi groups.