Fannie Mae Selling Guide B3-3.3-07 covers restricted stock units and restricted stock as employment income. In general, the income has to be vested and paid, with a history, and likely to continue. A grant letter by itself is not income. Unvested shares are not cash you have received.
Lenders do not all use the same average. Some follow the agency guide. Some add their own method. We do not run a calculator on this website that outputs a qualifying number, because using the wrong average would invent an income figure.
Bring the last two years of W-2s, recent pay stubs that show vested RSU payouts, the vesting schedule, and the brokerage statements that show the shares were released. If the stock price moved a lot, say so. The lender decides which price history it will use.