New job opportunity and breast cancer diagnosis

I recently was just diagnosed with breast cancer and will probably have to go through a mastectomy, radiation, and reconstructive surgery. I’m also in the process of interviewing for a new job with a new company and I’m pretty sure I’m going to be offered the position.

I don’t plan on telling the potential employer about my diagnosis at least until I have a written offer. What do people recommend? I think I want them to eventually be aware since I’ll have a lot of appointments to go to and need time off for surgery but I’m worried they’ll think I “scammed” them into giving me the job when I knew in advance I’ll need time off.

Also, will I be able to use my new jobs short term or long term disability benefits if I need to? I’m concerns my cancer will be flagged as a preexisting condition and my new jobs STD/LTD won’t cover it. I know I won’t be able to utilize FMLA since you have to work there for a year :/ Are there any other options for help to take time off?