I'm not sure what could be the bankroll or how much is your bet to be called as a high roller, for me my bank roll is around $500-$800 per deposit and my bet is around $50-150 per match (Sports betting) some people may think this is average but some people think this is high we have different perspective.
My average when I was still gambling back in 2015 is around 1k to 2k, that amount is a lot in my country, I could rake in around twice or thrice in a lucky day but a breakeven is what I strive when it is a bad one. You could say that I am sort of a high roller in my country because that kind of money in here is hard to come by. I do agree, perspective changes if you are a high roller or not.