u/Extension_Top_7474

https://preview.redd.it/qm2jixhvy0yg1.png?width=1890&format=png&auto=webp&s=26b1e0dc2b096561b3eb6516526e043c29be9acf

https://preview.redd.it/jsbzdaiwy0yg1.png?width=1137&format=png&auto=webp&s=c9b21ef6ba1aadc03766f41616e2f4307e50924b

https://preview.redd.it/401vjchyy0yg1.png?width=1102&format=png&auto=webp&s=492b0d865f716d9ae201ce05895a65d7c94dbcdb

I am trying to achieve what is depicted in picture 1. I've highlighted the specific line I am trying to bevel in picture 2, but whenever I add a bevel modifier, I get what is seen in picture 3. How the hell is it beveling a ton of lines I never even selected, and destroying the one line I did select?