How do i end a friendship

Hey there. This may be a silly question, but i'm really scared to tell my friend that i want to end friendship with them.

basically, i've just lost interest, and i thought that i better tell them abt it, then just to continue to ignore them and replying like idgaf.

also, we recently had a huge quarrel, and my friends and their friends told us to end our friendship, but this situation remained suspended.

also, choice depends on me, bc they told like "why should i think for you?"

pls, give some advices how to do it in a most polite way (they have anger issues, and i don't want to provoke a conflict)