I sleep trained both of my DC at 6 months. Now nearly 3 and 11 months old and both solid sleepers
Sleep training doesn't have to involve lots of crying and there are plenty of gentle methods which although take a bit longer, do help them to self soothe.
I agree with the first poster that you need to decide whether to keep the dummy or not. In 3 or so months they'll be able to put it back in themselves but until then it's a constant wake up to put it back. We ditched the dummy at the same time as sleep training with my first
We used the disappearing chair method with both and there was very little crying, we stayed in the room for the first few nights and it felt like the right approach for us.
Decide on a routine before bed and stick to it: we finished with a song and then put DC into their cot sat with the chair over them and shushed/sang etc. Patted bottom or held hand for 1 minute then took the hand out for 2 minutes (but kept singing/shushing etc). Keep doing it until they are asleep.
Next night the same but only pat when baby gets a bit upset.
Then again but move the chair slightly back and only get up to pat if needed
Then move chair further back
Eventually put baby down with the song and let them go to sleep themselves
For us, both DCs didn't really get too upset and almost instantly slept better
Good luck