Helper method to shuffle cards list for online gaming
4 bytes is only 4,294,967,296
Consider there are 52! possible shuffles = 8 * 10^67  

Use a proper shuffle like Fisher Yates. You get a proper shuffle with only 0-51 random.  Also shuffle from the prior shuffle (not a sorted deck). If you look closely Fisher Yates it produces exactly 52! deals.  It is perfect. 

I am not sure about your algorithm but I think the problem is that it will produce too many shuffles and they will not have uniform distribution.  I think it will produce 52^52 deals. 

A perfect random with a less than perfect algorithm is a bigger vulnerability than a perfect algorithm and a less than perfect random.  

You can use the regular Random and a proper algorithm and not be exploited unless they know the seed.  But it does not hurt to use RNGCryptoServiceProvider.

Poker security