Hawking radiation is an extremely slow process, for a black hole to evaporate through it takes a time frame that a human being simply can’t understand. On top of that, larger black holes take longer to disappear than smaller ones, so in this case it’s not really a concern for it.

Usually the limiting factor is on the ability to get big rather than stay big, if that makes sense! This one is a little bit below what we currently would consider the upper limits, though of course that may just be due to a lack of understanding!