How to add assembly code to the prologue and epilogue of all functions with the instrumentation code?

Question

everyone.
I'm working on a C project and I need a way to add assembly code in the prologue and epilogue of every function in the source code.

Let me give you an example.

This is the source code:

int main(int argc, char *argv[]){

    char buff[20];
    int a = 20;
    printf("Variable a: %d\n", a);
}

The relative assemly code is this:

0x0000000000001169 <+0>:    endbr64 
0x000000000000116d <+4>:    push   rbp
0x000000000000116e <+5>:    mov    rbp,rsp
0x0000000000001171 <+8>:    sub    rsp,0x40
0x0000000000001175 <+12>:   mov    DWORD PTR [rbp-0x34],edi
0x0000000000001178 <+15>:   mov    QWORD PTR [rbp-0x40],rsi
0x000000000000117c <+19>:   mov    rax,QWORD PTR fs:0x28
0x0000000000001185 <+28>:   mov    QWORD PTR [rbp-0x8],rax
0x0000000000001189 <+32>:   xor    eax,eax
0x000000000000118b <+34>:   mov    DWORD PTR [rbp-0x24],0x14
0x0000000000001192 <+41>:   mov    eax,DWORD PTR [rbp-0x24]
0x0000000000001195 <+44>:   mov    esi,eax
0x0000000000001197 <+46>:   lea    rdi,[rip+0xe66]        # 0x2004
0x000000000000119e <+53>:   mov    eax,0x0
0x00000000000011a3 <+58>:   call   0x1070 <printf@plt>
0x00000000000011a8 <+63>:   mov    eax,0x0
0x00000000000011ad <+68>:   mov    rdx,QWORD PTR [rbp-0x8]
0x00000000000011b1 <+72>:   xor    rdx,QWORD PTR fs:0x28
0x00000000000011ba <+81>:   je     0x11c1 <main+88>
0x00000000000011bc <+83>:   call   0x1060 <__stack_chk_fail@plt>
0x00000000000011c1 <+88>:   leave  
0x00000000000011c2 <+89>:   ret    

Now what I want to do is find a way to automatically add my assembly code in the prologue and epilogue when I compile it. And then get a situation like this:

0x0000000000001169 <+0>:    endbr64 
0x000000000000116d <+4>:    push   rbp
0x000000000000116e <+5>:    mov    rbp,rsp
0x0000000000001171 <+8>:    sub    rsp,0x40
0x0000000000001175 <+12>:   mov    DWORD PTR [rbp-0x34],edi
0x0000000000001178 <+15>:   mov    QWORD PTR [rbp-0x40],rsi
0x000000000000117c <+19>:   mov    rax,QWORD PTR fs:0x28
0x0000000000001185 <+28>:   mov    QWORD PTR [rbp-0x8],rax
// instrument code here...
0x0000000000001189 <+32>:   xor    eax,eax
0x000000000000118b <+34>:   mov    DWORD PTR [rbp-0x24],0x14
0x0000000000001192 <+41>:   mov    eax,DWORD PTR [rbp-0x24]
0x0000000000001195 <+44>:   mov    esi,eax
0x0000000000001197 <+46>:   lea    rdi,[rip+0xe66]        # 0x2004
0x000000000000119e <+53>:   mov    eax,0x0
0x00000000000011a3 <+58>:   call   0x1070 <printf@plt>
0x00000000000011a8 <+63>:   mov    eax,0x0
// instrument code here...
0x00000000000011ad <+68>:   mov    rdx,QWORD PTR [rbp-0x8]
0x00000000000011b1 <+72>:   xor    rdx,QWORD PTR fs:0x28
0x00000000000011ba <+81>:   je     0x11c1 <main+88>
0x00000000000011bc <+83>:   call   0x1060 <__stack_chk_fail@plt>
0x00000000000011c1 <+88>:   leave  
0x00000000000011c2 <+89>:   ret

I've done a lot of research on this. And I couldn't find anything that would explain how to do it.
I know that the gcc compiler offers the -finstrument-functions option to instrument the functions, but is not what I need. That's because that option involves adding these two functions:

void __cyg_profile_func_enter(void *func, void *callsite); 
void __cyg_profile_func_exit(void *func, void *callsite);

that in the relevant assembly turn out to be calls to those functions, and that's not what I want.

I've read that through a gcc plugin maybe you can get this result, but the documentation is really poor.
I also read something about DynamoRio, but I think what I need is a static and not dynamic instrumentation system.

Can someone point me in the right direction? Thank you all in advance!