Eric Olson and 'Memotech Bill' have developed a version of BBC BASIC (based on mine) for the Raspberry Pi Pico, it's a Work In Progress but is substantially working and can run all the example programs supplied with the Console Mode editions. There's a GitHub repository
here.
Despite the Pico being a $5 microcontroller with only 264K of RAM it suits this application very well, not least because of BBC BASIC's simple memory management (which was of course originally designed for a machine with only as little as 16K of RAM, the BBC Micro). Something like 240K of memory is available for the BASIC program, variables, stack and libraries.