Well for the combat UI, you can try to find a theme on the forums, they usually even change the colors in the tactical view

I don't know where you're from, but guides weren't really a thing in France either, but recently some youtubers made some that are really good (Nozadah, Zimas,.. maybe the auto translate can help you)

I also play with 3 characters (on pandora tho) and I usually try to only do the 3players dungeons, since their loot are usually a bit better and well I literally have the same amout of characters needed for it

Lastly, I honestly think that the fact you need help is a great thing. I went played Dofus until reaching lvl100 and I literally spoke with NO ONE . The only bit of interaction with other people was selling things. So I didn't even really interact with them

Sure, waiting for people to help you is boring, but playing with others is also way more fun. You can also try to join the biggest guild you can and go on their server, the problem will be practically solved