Look up for faster whisper or distilled whisper models, smaller models run quite nicely but perform poorly outside of English, if you are interested in a different language it's better to finetune it (HuggingFace has a huge amount of finetuned Whisper models).

Best CPU TTS that can run on something like a raspberry pi is Piper. It can do real time synthesis on a raspberry pi and on a real computer it runs several times faster with negligible performance cost. I use it for 'reading' ebooks when my eyes get tired. The quality is roughly on par with where Mac OS's TTS was ~10 years ago (the last time I used it.) You can tell it's TTS, but it's good enough that you can become accustomed to it fairly easily.

https://github.com/rhasspy/piper

If you want real-time, it requires a GPU, but can be underpowered. CPU is a little slower but works fine.