Actually if you put him down later he may still wake up same time just get less sleep and be over tired. Whomever told you that is wrong.
Nah any time we’ve tried to keep our baby up late he wakes up even earlier I swear! He goes to bed around 7, sometimes even earlier if he’s had daycare all day and he’s exhausted
No, you are not putting him down too early. 7-8 is typically the sweet spot. 10pm he will be overtired and will probably still wake up early bc an overtired baby/kid doesn't sleep better. He's likely waking up for feedings out of habit. Have you tried increasing solids during the day to see if he's still waking for night feeds? I'm lucky and my son dropped the night feeds on his own, but you can do dream feeds and slowly increase the time between them. Have you joined any sleep FB groups? There's typically a ton with some great help. I know Taking Cara Babies is a great IG account that is geared towards sleep and she has tons of free resource.