I've had similar experiences to the OP. I went ahead and rolled a simple green thread timer. It doesn't support actual process management like a real kernel,

I've had similar experiences to the OP. I went ahead and rolled a simple green thread timer. It doesn't support actual process management like a real kernel, and doesn't make any guarantees about anything, but it has gotten me further than bare metal scheduling and helped me avoid the shit show that is RTOSes. Think JavaScript timer callbacks with an optional context struct (in C) It has allowed me to interrogate a variety of sensors, process inbound signals, make control decisions and emit commands, all at various frequencies. I highly recommend folks try something like this before ruining your life with these slow, abstract architectures.