To convert a TTS sound into an imported sound: triple click and copy the link into the URL bar, download the sound and import it into your project. If you use the given pitch effect, it should sound the same as the TTS blocks, but without the delay
I've tried to replicate the way Scratch generates the link where it gets the TTS sound from. https://github.com/scratchfoundation/scratch-editor/blob/384613f15ac47077ae0ee2193eba0ede8956c9c8/packages/scratch-vm/src/extensions/scratch3_text2speech/index.js I've got the data in the "TTS..." lists from there. I've got the list of white-space characters from https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_expressions/Cheatsheet and I got the list of forbidden characters by listing all characters whose unicode code point is less than 160 but aren't listed as allowed at https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent and I also added the white space characters to the list of forbidden characters. The "blocks & texts" sprite is a modified version of the one in my unfinished Scratch simulator: https://scratch.mit.edu/projects/708323679/