I concur that RTIC isn't appropriate here. It works for most of the applications I've had, but it sounds like this is an exception. Regarding better mutexes: I will cheat. What I'm about to post is just a macro that does not really abstract, but it makes the syntax cleaner by allowing most of the boilerplate to go away, so you can focus on the semantically-meaningful parts:

Declare:
```rust
make_globals!(
    (FLASH, Flash),
    (SPI1, Spi<SPI1>)
    (CONFIG, Config),
);
```
Use:
```rust
access_global!(CONFIG, config, cs);
```

or:
```rust
access_globals!([
    (CONFIG, config), 
    (FLASH, flash),
], cs);
```

Init:
```rust
    init_globals!(
        (FLASH, flash),
        (CONFIG, config),
        // ...
    );
```