Insufficient information.

What additional info would you need?

You'll need to show the elements you have described;

" I discovered a load bearing beam (=two 2x10 attached together spanning the length of two rooms)."

"the joists are sitting directly on the beam."

"Also, the angled studs(on which the roof boards and shingles are attached) are joining the joists right above the beam."

You can slice the joists and run a laminate beam in the attic, between them, connecting the joists to the lam beam with joist hangers rather than resting on the current beam. It's delicate surgery, in that you have to make sure you're supporting the joists on either side while you remove the beam and install the new one. But it's something we did DIY a few years ago.

Have the beam company engineer it for you (free).

Below is a link to my post asking for help with our endeavor, including a reference to a great article in Fine Homebuilding that was very helpful.

Good luck!

Here is a link that might be useful: Installing a flush lam beam