I've read so many unfavorable reviews about the Bernina 770. I'm so sorry that you spent a lot of money and been disappointed with your machine.
I've only owned one Bernina (440QE) and was not able to "bond" with that machine so I sold it. I've also owned 3 different Janome models and sold them all. The latest one was a 9450. I spent more time trying to figure out what foot to use, what plate to use, and watched more videos than you can imagine because the manual is terrible and the interface is so complicated, it was frustrating. When I sold it, I had hardly sewn on it. The biggest gripe I have with Janome machines is their difficulty with sewing over several layers of fabric. I'm strictly a quilter so there's always seams to cross. The machines would struggle and stop sewing when they got to seams. Another annoying feature is how loud the Janome machines are. Drove me crazy.
I'm a Brother gal from way back (I'm 78) and they've always been reliable and quiet. I have a Nouvelle 1500 that I've used for 14+ years and it's still a workhorse. My newest Brother machine is the Innovis BQ3100. I love the lighting, the 11"+ harp space and laser light. It's smooth sewing and so very quiet
It's hard to find the "perfect" machine. Good luck.