Girls hi! I rock my little one to sleep on a bouncer every night, of c…

Girls hi! I rock my little one to sleep on a bouncer every night, of course he's gotten used to it. The back gets more and more painful with each kilogram, even when rocking him on the bouncer. I would like to retrain him, but I don't even know how, because the baby starts crying and fussing when he wants to sleep, and when I put him down, he has full-blown tantrums and cries. I think my nerves can't handle retraining him to something else. I don't even know where to start. At least not self-soothing, just that I would be lying next to him and clap my hand to make him fall