Im desperate to find an easier way to put my 5 month old to sleep

A month ago we went on a vacation and had a big family get together, the only way he would sleep there (because of the loud noises) was by putting him on a pillow, taking both sides of the pillow and rocking him. Now thats the only way he will sleep

As he is getting older and heavier, its taking him longer to fall asleep (30 min of rocking) and my arms get sore by the time he falls asleep ( he weighs almost 23 pounds)

Im honestly so tired of forcing his sleep and I’m worn out i need some way to snap him out of this

Btw he is breastfed (sometimes he will fall asleep on the breast randomly but only if I’m laying in bed)

If you have any children, how old and how do you put them to sleep ?

P.s i can’t use the cry it out method because grandma lives with us and physically will not tolerate that she doesn’t want to hear him cry that much lol