HELP

I'm a newcomer. This is the skin I made. I hope you will like it. Additionally, I'm posting a request for help:

I'm playing the Better Oneblock modpack (www.curseforge.com/minecraft/mc-mods/better-one-block/comments), but I've run into two issues.
First, all the in-game menus are showing a lot of garbled text. I suspect it's caused by a mod incompatibility, but I don't know which specific mod is responsible.
Second, during gameplay, I triggered a special event that spawned a ton of monsters. At the same time, structure blocks were somehow generating right where normal blocks would normally appear. I can't destroy them in survival mode. I tried typing the command /gamemode creative in chat, but it didn't work and gave me an error. Because of the garbled text, I can't read what the error says. Could anyone help me fix these problems? Thank you!
(P.S. My English isn't very good, so I used a translator—sorry for any awkward phrasing.)