Personally, I've begun switching over my RP2040 projects to Rust using Embassy. Rust did take some getting used to, but I quite like it. Not an RTOS, but it satisfies a lot of the same requirements that'd lead you to an RTOS.
Rust and Cargo take the pain out of building and flashing to the RP2040 (or STM32, for that matter) - it's the most pleasant embedded setup I've ever used.
A lot of applications simply don't use the MPU. And then consider what you get from Rust memory safety and the reduction in overall complexity of the firmware without the RTOS.
Embassy has it's own HALs which makes it better at async and has also nicer ergonomic IMO
I’m using RTIC for the firmware on my STM32H7 based product (https://umi.engineering) and it has been a joy.
Worth noting, you don't HAVE to use the embassy HALs with the embassy executor. However, AFAIK, the only mainstream non-embassy HALs that supports async is the ESP32 HALs.
There's no technical lock in, it's just that everyone I've seen implementing async support (outside ESP32) tends to do it within the Embassy project today. That may change over time.