Whatever web host you use for your wordpress site will make no difference in your SEO rankings.
Just moving your website to a web host that claims your seo ranking will improve if you host with them will not work.
Improving your ranking takes time, research and writing great content that google will love.
The host you're hosting your website with makes no difference unless your hosting your website on a slow server that takes forever to load your website and goes down frequently.
As long as you have a fast web host and not too much downtime you should be okay.
If your website is still young such as under a few years old and your website is still not ranking you just need to give your website time to age and climb up in the rankings.
I had a website take 5 years to climb up the google rankings so you have to have patience when running a website and getting traffic.
Google favors older more established websites over the new just put online websites.