Flamegraph not displaying user-defined functions

[jpmedinagl]

I'm working on a project using flamegraph and for some reason I can't get Flamegraph to display user-defined functions. These are my configs

[dependencies]
libc = "0.2.155"
faer = "0.19.0"
flamegraph = "=0.5.0"

[profile.dev]
debug = true
opt-level = 0
debug-assertions = true
strip = false

[profile.release]
debug = true
strip = false

This is what I use to create the flamegraphs (in my base Cargo.toml, I cloned Flamegraph so I could access stackcollapse-perf.pl and flamegraph.pl)

$ perf record -g ./target/release/basic
$ perf script > out.perf
$ ./Flamegraph/stackcollapse-perf.pl out.perf > out.txt
$ ./Flamegraph/flamegraph.pl out.txt > flame.svg

My project is over 1k lines of code so I'm not sure why user-defined functions aren't showing up

I also tried writing a random test file with a loop to try and see if I could get it working aside from the project. I also tried using blackbox to try and block out optimization.

use std::hint::black_box;

#[no_mangle]
pub fn sum() -> i32 {
    let mut sum = 0;
    for i in 0..1000 {
        sum += std::hint::black_box(1);
    }
    return sum;
}

fn main() {
    println!("Sum: {}", black_box(sum()));
}

I also checked and the file has debug info and is not stripped

$ file ./target/release/basic
./target/release/basic: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=e36e552eded3fad47af12fd3b0ab9049b0f0a524, for GNU/Linux 3.2.0, with debug_info, not stripped

I also tried running with dwarf which just produced a different flamegraph

$ perf record --call-graph dwarf ./target/debug/basic
$ perf script > out.perf
$ ./Flamegraph/stackcollapse-perf.pl out.perf > out.txt
$ ./Flamegraph/flamegraph.pl out.txt > flame.svg

I'm not really sure if I'm just missing a setting or something. But I can't seem to get flamegraph to display any user-defined functions. Is there something I'm not considering?