My current website on Wordpress is using WPML. I've made a choice to usehttps://domain.pl/ for English Content https://domain.pl/pl for Polish ContentThe goal was to have directory based redirects. Since I own .xyz domain now which is global along with other domains such us .support/.solutions etc I was wondering if it's worth the effort to split them so thathttps://domain.pl gets Polish Contenthttps://domain.xyz gets English Content and goes globalThe effort i'm talking about is doing all the redirects, reconfigurations etc. Will it give me much higher SEO boost or should I just focus on adding more and more content? I have a feeling that https://domain.pl/pl doesn't have much visibility because of the /pl (and as such Google webmasters also treats it differently). 
Is it worth the effort to split one multilanguage wordpress domain into multiple domains?
seo;wordpress
Yes, it is worth it. although you can use meta tags for location and language, but it seems Google treats ccTLDs (.pl, .us) differently and they get better rank in local searches than international searches.I think it is worth it to have a gTLD (.xyz) for your English, or international versions.You can also provide all languages on your .xyz, then redirect the .pl domain to domain.xyz/pl/ or pl.domain.xyz.