I'm sorry that you are facing these challenges with Sasha. Sounds like you are doing a good job with frequent outings and walks, and keeping a fairly regular schedule for potty breaks.
The only additional advice I can give you is to always praise Sasha when she potties outside. Praise her profusely and give her a pat on the back or chest, scratch behind the ears, or whatever she likes. Perhaps even give her a little treat (keep them in your pocket and have them readily available). I believe praise has been key to my success with my two boys.
When you do need to leave Sasha unattended, confine her to an area or small room that has flooring that is easy to clean (i.e. tile). Use baby gates if necessary. That will give you some peace of mind and you will be able to tell more readily if there have been accidents. You can do this her entire life if necessary. I put my guys in their "romper room" (bedroom) when I need to leave them.
Best wishes for success with Sasha!