I went looking for this answer and all I found was that there really isn’t any way to find a total number of coins. You can do the math using the statistics to get an idea on how many coins you have or see your coins for a specific period, but not for the total you have at the moment. There’s also the little bit under your profile on the right that has coins earned in 30 days
I suppose if you haven’t spent any coins or you can find a point in the coins earned stat recently where you had 0 coins you can use the cumulative all-time coins stat, but that’s a bit of a hassle. I found an old post detailing that but there’s not any way currently to find this number in the UI.