Looking back at my friendship with someone

Ive been looking back at my friendship with someone I used to consider my best friend and wow. Genuinely didnt realise how one-sided and how much emotional labour (?) I was doing for her. At first I didnt mind because I knew she really needed it and wasnt constant. But over the years its become so much. Obviously not online anymore bc of how distant we've become but in real life its just exhausting. It wasnt even like this at first and our friendship was good, i dont even know what went wrong.
I get we dont have much else to talk about but its just the same points over and over again all day, theres only so much validating and different responses or advice I can come up with to the same situation. Its always something which pops up or happens atleast every couple of weeks.

And I get how exhausting it must be for her, but at some point I just cant really feel sympathy anymore. It just makes me feel like shit because it just doesnt feel real anymore because stuff just keeps happening because of the friend group she's in. Not the best comparison and probably insensitive but its like im watching an interactive drama show or something. I feel so bad but I honestly just dont care anymore. Its horrible that she's stressed but there's not much I can do. I cant imagine how much it'll be for her other friends because we barely speak anymore and I find it overwhelming sometimes.

Ive become close to some other people and I genuinely notice the difference in how I feel with them vs her. They actually listen to what im saying and respond with things which are "oh yea, mhm" or some other way to end what im speaking about. I dont really feel the need to say things quickly because I dont want to be cut off or waste their time. I can be as silly/cringe as I want to be. I can majority of the time tell them stuff which is bothering me without fear of judgement or shit talking. It isn't mostly just me planning stuff to do. Its honestly so nice.

Idk why i even wrote this. I just think I need to share this with someone other than my mum. (Can't tell my other friends all this cause they know her and I dont want to seem like im shit talking..)