People want you to fail because they are insecure fucks. Most feedback is projection or inserting bullshit to make themselves feel better.
Listen to feedback but be critical about it and understand the context in which it is being provided. Nobody gives two fucks when someone who looks like Roseanne Barr gives diet advice, they just move on but if someone is threatening, it’s suddenly a dick measuring contest.
Keep.doing what you are doing and don’t be like these dicks, build others up on your way up.
Out of interest, did any of them, even one, have any evidence that they knew anything whatsoever about training? At the end of the day, run your mouth all you like but I don’t give a shit what you say until you show me the money. Did any of them post their own physique pictures or was it all just fat 14-year-olds flapping their gums?