i don’t think there’s an exact number. A high stat is a high stat, and it can vary depending on situation on opinion.
The website here uses colours for stats of the pokemon. Red, Orange, Yellow, Green, and Teal. The “green” starts at around 90, which that, I personally would consider good/high. I’m not sure if there’s a set number, or offical number, of if that’s just what the site admin decided on a whim. You think 120 is the baseline for a stat being high, and I consider the green 95 to be high.
What’s your definition of high/good? Are you asking about opinion, or what’s “officially” classified as good/high? Good/high for what? There’s definitely times where lower stats are considered better, like a low speed would be good for trick room. Are you trying to ask about what’s good for each stat competitively?
Ultimately, opinion wise, if you think 130 is good and that 100 isn’t good, you’re absolutely entitled to your opinion. 130 is higher than 100, after all.