I’m not sure how one separates this question from hosting, so I’ll counter another untruth, rephrase/summarize, and bow out.
Most managed WordPress hosting plans use Litespeed as a primary webserver, including those from all three of the hosts on www.ads-software.com/hosting.
To the OP: if you have shared/reseller hosting, you can’t change your webserver, no matter what it currently is. If you have VPS/dedicated managed hosting and your hosting panel is cPanel, you probably can’t change your webserver to nginx without violating your support agreement. For anything else, the links provided will point you in the right direction. Other resources are wordpress.stackexchange.com and webhostingtalk.com.