This is an inexpensive 433MHz module (around $10) found on AliExpress, based on the ASR6601 chip and featuring a 1W RF power amplifier (PA). Additionally, it includes an LNA, so the receiver should be more sensitive.
I have prepared custom firmware specifically for this module, which can be flashed using the ASR6601MultiProgrammer tool.
To enter bootloader mode, one of the pins must be connected to +3.3V.
Programming can be done using any USB-to-UART converter; however, make sure it operates at 3.3V, not 5V. The photo shows a converter provided by the module manufacturer — it works as expected.
Next, flash the configuration as usual using the new tool version 3.11.
And that’s it. By the way, one of the modules I bought unfortunately appears to be faulty and only outputs 0.5 mW of power, so it’s always a good idea to check whether the output power is correct.