Will this screen match the original Note 20 Ultra display?

It is built to fit the Note 20 Ultra, but replacement panels vary. Expect the same size and curved shape; brightness, color accuracy and touch response may not fully match Samsung's factory panel.

Does the S Pen and fingerprint sensor still work after replacement?

They should, since both depend on the display assembly. The in-display fingerprint reader and S Pen digitizer are part of the screen, so a poorly made or badly installed panel can make either unreliable.

Can I install it myself?

It is a difficult repair. The Note 20 Ultra uses curved glass and adhesive, and the screen must be separated from the frame. Most owners have a repair shop do it.

Will the phone stay water resistant?

Not reliably. The factory seals are broken during the swap, and water resistance depends on how carefully the new screen is resealed.

Is it worth repairing a Note 20 Ultra?

If the rest of the phone works, a screen replacement is far less than a new flagship and keeps the S Pen and 120Hz display. If the battery or other parts are also failing, weigh the total repair cost.