Weird text appears on top of my page

Hello,

Please try to disable the wpfc-minified plugin.

Oh, I don’t have that plugin installed.

You don’t have this plugin installed: https://www.ads-software.com/plugins/wp-fastest-cache/faq/ ?

ops, that, I have. should I disable it?

Yes, please temporary disable the plugin and check if the issue disappeared.

I did it and the issue disappeared. Although, that plugin helps a lot when I am changing something on my site, should I permanently disable it for the issue not to recur?

In this case the only thing which I can advice is look for another cache plugin like WP Super Cache, W3 Total Cache or analyze the current plugin settings – maybe it is a reason of wrong configuration.