Apply shading to alternate rows in a worksheet (No Conditionals or Tables)

Hi All! I'm big on formatting but have recently had trouble as formatting effects storage size. In the past, I have used conditional formatting to apply shading to alternating rows in a table. As my data set began to grow (100k+ lines) this exponentially grew my file size and slowed the calculations wayyy down. I tried moving to using the insert table capability to create the format then revert to change to range to get rid of the table. This was worse.

 

Does anyone have a solution? Thanks!!!