6 months is very late to be getting baby to accept a dummy. You may have left it too late. The earlier they are introduced the easier they are to establish. Especially in a bottle refuser who's not a fan of teats.
Having said that, using dummy independantly is a different and seperate matter. It's developmental.
How is baby's pincer grip? Passing things from one hand to the other? Placing objects down rather than letting go? Manipulating and turning objects around? These are all skills baby needs to develop to be able to use a dummy independantly. In my experience it happens in the 7-10 month range.
There are things you can do to practice. Hand dummy to baby in hands every time, so he puts it in himself. Hold dummy out of reach so he has to reach for it. Give dummy the wrong way around so he has to turn it over before putting it in. Place dummy out of eyeline (at feet for example) so he has to move to get it.
These are all developmental skills and it's unrealistic to expect baby to be able to use dummy independantly until physically capable.
I kept the cot by my bed until baby could do dummy inserts independantly. Until then, being able to do dummy inserts without getting up out of my duvet or even opening my eyes makes a big difference.
I am not sure i would be inclined to get up, walk to another room, dummy insert and settle, then walk back to my room every time it was needed. Not a problem when you have a dummy user who is sleeping through. But a dummy user waking in the night still, no chance I'd be ploddibg from one room to another all night. I'd be too knackered to cope with that.