Libre 3+ Issues AGAIN

Basically as the title supplies, I'm having issues using a CGM again. I wanted to attempt to use one after having a multi month break (mostly for my mental health). But I try to be a good diabetic and care for my blood sugars, so I figured if I used it again maybe I could have better control.

I have a libre 3+ currently on the back of my arm. I am very skinny, and presumed my issue previously was that I just was injecting too close to a muscle. I tried to find a fattier point on my arm. First 24 hours were great, even only 5 points off at one point. But twice today (once this morning, and once currently), it has been 100 points off. It said I was 123, I was 226. Now it's saying I'm 130, and I'm 245.

I want to give up and cry. I really had hope that things would've changed, but they haven't. This is the same issue I experienced with the Libre 3+ before. It's mentally driving me insane, but I desperately want to have a CGM to back me up in between treatment decisions (I always fingerstick before dosing). I just want a general idea of where my levels are.

What am I doing wrong? I've posted before, and gotten a ton of advice about proper sensor insertion. I've followed it all. But it never sorts itself out, and I always end up with 100+ point differences.

30 off is okay. Hell at this point even 50 off is something I can work with!! But how do people connect CGMs to closed loop pumps with differences like this? It's so dangerous!

I know it isn't me, I'm following correct procedures. Are some people's body's just not compatible with CGMs? The Dexcom G6 worked for me so well, maybe it's because it was a slanted filament (angled insertion), and I'm very skinny, so it never hit muscle?

Are there better places than arm? I cannot use my thighs, I have no fat there. My tummy is also very very flat, but it might be a choice? I have some insulin scarring there currently.

I just feel so alone, and like everyone else has a great experience with a CGM. I also want the 5.5 A1C people have. Even a 6. I'm just so sad, and this is making me feel depressed and want to give up on the CGM like I have twice already. :(