Hey, Eugene from Weglot here.
I’m sorry that you’re experiencing slowdowns.
* Having a Spanish option does improve your SEO! All your translated pages are automatically indexed on Google so it’ll bring you new traffic from a Spanish-speaking audience
* Weglot is only “creating” the translated pages and translations at the first visit of a page (by a human visitor or bot). So the added response time should mainly happen once and then the response time should be a lot quicker
* Then your translated pages are cached by your cache solution too so it shouldn’t slow down the speed (on mobile and desktop) once they’re are cached