Dear OP, I believe you can do better

Something that may be a bit hard is to separate the bad and good parts of criticism. When someone critices you in a bad way, I encourage you to filter out the frustration from that person and only keep the valuable information for yourself

If in this example, you leave with the mentality of "Man mentor sucks" instead of "I wonder how can I improve this" then you lost. Think about it as, you being better than them, you shouldnt let their bad words get into your head, but at the same time, try to understand where the unasked advice is coming from

Here is a unrelated personal experience, my own mentor moment if you will: I did a expert roulette and got smileton (Early endwalker), trough the run I noticed things were dying... slowly, then I noticed the summoner was only using summons in bosses, and ruin the rest of the time. By the last pull before the final boss, the feeling of frustration was building up on me (as I was a SMN mainly player at the time), so I asked, "is there a reason why you are only using ruin?", and a couple minutes later after the boss, the other dps replied "My wife doesnt play much videogames, but she would appreciate if you could elaborate further"

With that, my hearth sunk, I was feeling frustration for someone doing their best, and, as requested I explained gemshines and how summons can be rotated without much issue, blah blah blah... but it always stuck to me how, well, ANYONE can be playing on the other side of the screen. So for anyone that took the time to read this, please, try to be mindfull of how you bring things up in chat