Yes you can use Elementor and WPBakery / Divi at the same time.
But I WOULD NOT suggest it, as it will affect the performance and speed of the website.
The reason is if your website has Elementor and WPBakery / Divi installed, your website will load CSS and Java Scripts from both page builders, plus tons of shortcodes and it gets even complicated if you need to debug the website.
Size of WPBakery website
When I import a basic Business demo, the page size increase to 2.06mb with 158 request, fully loaded time increase 1.4sec to 3.3sec
Size of WPBakery and Elementor website
Let’s try edit WPBakery website with Elementor with one headline.
For additional of a SINGLE headline, the page size increase to 2.09mb with 171 requests, fully loaded time increase another 1.5sec to 4.8sec. You can see the impact is crazy. Furthermore, it breaks the layout, the slider no longer working.
If you are using ThemeForest / WPBakery / Divi and want to have some Elementor function, I’ll suggest you convert/rebuild your WPBakery website to Elementor. With some addon like Elementor Extra or Piotnet Addons For Elementor, you basically can build any website that is more functional that WPBakery.
Convert WPBakery to Elementor page builder
If you wish to convert/rebuild WPBakery / Divi website to Elementor You may follow my guide Rebuild / Convert WPBakery Page Builder / Visual Composer to Elementor page builder.