Amdhal's Law would suggest that much of the 750ms latency is likely attributed to I/O operations (mainly DB ops) and not CPU. Also, without knowing anything about your setup: upgrading to PHP 8 and/or enabling opcode cache may help. All that said, my original quibble was with development time, not run time overheads.

750ms transaction times and it’s “the language” that’s the problem? Not bloody likely.