Hi! It really sucks that Minecraft Java doesn't let us use the § symbol to color signs and/or make them bold or italic or anything else like that, but this mod fixes that and has a really simple user interface that is pretty easy to use.
https://www.curseforge.com/minecraft/mc-mods/color-unchained
If i could please request the Aternos Team to add this mod it would be amazing, now i know it doesn't have the 1k downloads yet but it is the only mod for my version of my server and really one of the only mods of it's kind.
Thank you!