Graphics, lagging, fps, and other annoying problems

Hi community! Since BG and pirates (specially with all the buying and selling with Hoggarr) I've realized that the game looks slow from time to time.

I have a good pc but a terrible internet connection.

I'm trying to find is there anything I can adjust to make graphics work faster, googled solutions, read on reddit and watched some vids, but I have still some questions and I was hoping someone here could give me a hand:

How can I know what's really causing the slowness?

Some of the solutions involve modifing the "options.txt" file: is that really secure or could be a reason to be banned?

Could we eventually have an official OoC post about how to make games perform better (assuming this might be an issue with MTG and LoR).

Thanks for any tips and help!