I had the same problem. Bread did not work. But what did was using another torch heat the pipe 8 to ten inches away. The water will heat and evaporate allowing you with the other torch to make the solder connection.
I once shoved a 3/4" pipe full of bread and plugged every thing downstream of it.
I've had a plumbing disaster going on here for a couple of weeks. Old house - fix one leak, another one pops up a few days later. It has a crawl space so I really need to fix each leak once and be done, so soldering isn't going to work for me. Sharkbites it is.
I've had a lot of people tell me Sharkbites are junk. I ask them if they don't work, how are they still in business. The "nothing better than solder" gang never volunteer to come over, crawl under, and help, either.
Just be sure to debur and mark the correct insertion depth and there should be no problem.
I considered buying a pro-press setup then realized I could have the house replumbed twice for the same price. They make them now with a hand-held hydraulic pump that are inexpensive, but I don't know how you're going to make them work in tight spaces.
FWIW I've got a couple of independents coming over tomorrow to price ripping out all the copper and switch it to PEX. It's going to hurt but it should outlast me and that's what matters at this point.
