Interesting idea, having the spellchecker would correct the spelling when it gives you a dictionary definition for a word. That might help you avoid learning a misspelling.
But if we’re importing real-life people speaking out in the wild, some of them are going to mumble and make mistakes. It’s probably something you just need to get used to.
One of my friends is very literary, and thinks I should only be reading high-quality texts, not translations, not a bunch of chatter from random podcasters. The “high quality input only!” approach makes sense if your first objective is improving your writing and literary style. For me, I enjoy improving listening comprehension, so the mumbling, typos, and awkward turns of phrase are a feature, not a bug.