A baby of that age is too young to be left to "cry it out" as they don't understand, but you wouldn't be doing that as this is the gentle parenting discussion. But I think a baby that age can learn to "self settle" if you can find something that works for you. My DS goes off to sleep no worries, took us till about the 3month mark to realise he could do it, but like I said one day we just found what worked. I too was tired, not getting a sleep myself & was beyond myself. If you don't want them to self settle or it doesn't bother you then don't stress. Otherwise you could try several things, a dummy (if you are not bothered by them or not using one already), music in the room (my DS has radio on 24/7, louder during the day), a wrap or something to cuddle, quiet time before sleep like a small cuddle in dark room & perhaps sing to bubs.

With DS I always put him down not long after a bottle, sometimes I feed him the bottle in his room (in dim light), then I give him his dummy & wrap, he'll cuddle into it & then me. I give him a cuddle, hum a bit then pop him into his cot & walk out of the room. It's been working for us from about 4months & does make things so much easier.