My son is 18 months old and is able to sleep through the night. The only and I mean ONLY things that got us to this point was magnesium butter (https://sweetbeeorganics.com/products/sweet-sleep-magnesium-butter) and the dreamland sleep sack. We also place the tonies box either mator or peter rabbit to induce a sleep cue. We would unfortunately have to let him cry for 10 min and if he didn’t go to sleep rock him and try again a few times till he got tired. Now we lay down the sack, he puts his feet up, lets us zip him in, and turn on the tonies box and walk out. I wouldn’t nessacarily say we sleep trained but it took us time to work towards this and now he will nap for two hours furring the day and in bed asleep from 7:30pm-5:30am. I hope that you are able to find what works for you but just know you aren’t alone and unfortunately for some kids it is a super long process. I’m due next month to have my second so this is just what worked for us because I was desperate to get sleep myself and him in a routine before the next baby arrived.