suspect malware Strange code in wp-config.php

Hi, from a bit of time i have experiencing some changing in my blog styles view.
To improve page speed i have installed a total cache plugin, but after a few days problem initiates, styling in admin dashboard and styling in login page and difficulties in styling frontend pages and post. others told me to disable caching css and js, so i have removed the cache plugin, but still remain the problem. So I start investigating my files, and i have found something very strange. I think it could be some kind of infection but i am not really sure.
I have installed wordfence and now is running scan, waiting ending of process but no malware found (it says secure).
but i have strange things in htacces file and in wp-config file.
the htaccess is empty (only begin and end), no mod_rewrite.c section or else.
The wp-config have to the beginning a strange piece of php functions set. i havem’t seen before in the other blog i have, so this is why i think it could be an infection.
Today, i have tryied to access from my mobile and a redirection runs loading a strange page saying me that my android have a virus.
these are the page i registered in my cronologies
wonderlandads.com, mobile.bitterstrawberry.org,android.security-center.com that indicate that my smartphone was infected. (i have installed avira a scanned but no treats found)

I have tryied to replicate that thing but nothing happens, no visive modification to my blog or else.
wordfence is still scanning my blog is very big.
But for that function in the wp-config could you give me some advice?
i have to delete? or not.

thanks

https://ww.wp.xz.cn/plugins/wordfence/