fluorescent lamp messing with voltage in the house
Change it to an electronic ballast

There's nothing wrong with fluorescent lights inherently.  However the early fluorescents relied on a design which was before electronics (and therefore, before anyone cared about line noise). 

Fortunately, electronic ballasts came along in the 1990's, and they made things much better.  It isn't hard to make an electronic ballast that has very little line noise and an excellent power factor, and also drives the fluorescent tube much closer to optimum conditions. 

So, identify your tube type, identify the physical location of the ballast inside the lamp, and shop for a ballast that is a) rated for that tube, and b) physically fits (there are standards for fitment, so it will typically have screw holes in the same places). 

If that proves difficult, then shop for an LED replacement "tube".  Those come in 2 varieties: Plug-and-play (does not require ballast to be wired around, BUT depends on the ballast being there) which is stupid.... and Direct-wire, where you feed it mains power directly and the ballast is bypassed. 

Mind you, I am biased; I think real fluorescent is a perfectly fine technology and I continue to invest in it.  You may disagree when that tube burns out and you have to spend €30 to replace it!  However if you don't see dark bands on the ends of the tube, that'll be a long time, especially with an electronic ballast.