Crop without losing quality

I am pulling in video from a webcam as well as slides from Zoom. I am placing them side-by-side (I do not want to use the screen share and speaker view as the speaker is too small in the video). I crop out the sides, top, and bottom from the webcam video to make the speaker larger. However, it no longer fills the frame and is really small. I select "Zoom" in Effects but it makes it blurry. What is the best way to crop off sides of a video in Premiere but yet retain the same size and not lose quality and get blurriness? Thanks!