It seems that the background image is coming from the page builder so you’ve to remove the dark overlay from there.
Follow the steps to remove it.
Step 1) Go to pages and open your home page with Elementor page builder.
Step 2) You need to select the background image section in Elementor page builder which then opens up the Edit Section tabs on left (ie Layout, Style, Advanced)
Step 3) Click on the Style tab and then on the Background overlay.
Step 4) From there you need to click Clear button on the Color panel
Step 5) Update page.
There are videos also which can be helpful. For eg check the video below