you aren’t being unreasonable.
I figure that if adults would prefer to fall asleep next to someone then a baby would too.
Some adults also need help getting down from being upset so it makes sense that babies would too.
I think of it in a would I like that and if the answer is no then there’s a 98% chance the baby won’t like it either.
My son who is now 19 months was THE WORST sleeper, to the point where I would actually cry with him. He would go to sleep around 8, wake up at 10 and cry until 11:30; fall asleep, wake up at 1:30 and scream until 4:30/5am, wake at 6am and being his day. This went from about 10 months until 17 months and I very nearly went insane.
Leaving him to cry didn’t work he would just go for hours (and it broke my heart), going and giving a cuddle then coming back didn’t work either. I just sat next to his cot for hours at a time while he tried to fall asleep and now finally at 19 months we do a story, one cuddle and he lays in his cot and falls asleep. He also now settles himself in the night too (only started happening in the last month or so). Way better sleeper than his brother.
My partners son who I met at 17 months old was left to cry it out and come back in 2 minutes/5 minutes etc etc is now 5 years old. I am yet to meet a 5 year old as bad at sleeping as he is. If he wakes up for whatever reason he can’t get himself back to sleep and will lie and cry, he also can’t get himself to sleep and sits in this state anxiety that he’s going to left alone. This isn’t the case for all babies obviously - this is the only child I’ve known well enough to comment on.
You’re the mother. You know best. The sleep trainer doesn’t know your baby, isn’t familiar with your baby, doesn’t know their habits, doesn’t know how they calm down. If it feels wrong to you then don’t do it.
Babies will outgrow most things, when I was a preschooler I used to have night terrors and would scream, squat, pee on the floor and then continue screaming, cry for about half an hour then go back to sleep as if nothing had happen. I don’t do this anymore - but my mum thought I’d never get over it (I did this every night for about a year between 1:30 and 3:30am).
But she’s a baby, only 11 months I’m 98% sure she will outgrow bad sleeping. (I’m solely basing this on having a real life demon during the night for 9 months).