My projected Federal return for 2020 is $923 & tax withheld was $3,309. My 2019 Fed return was $2,458 & tax withheld was $6,989. Why is my return for 2020 much lower?

Without looking at your return it is hard to tell why your refund might be less this year. However, from the numbers that you are posting, it looks like the amount of tax withheld in 2019 is almost double the amount of tax withheld in 2020. 

The amount of tax that’s withheld throughout the year affects how much you’ll be refunded (or owe) at tax time.