The multilingual support always predict words in all languages, even if you started a sentence in a specific one. And it will follow the typo rules of the first language in the list. For example, if the first language is French, it will add a space before the interrogation mark (French rule), even if you’re writing in English.
I installed Tubular today. It’s a fork of NewPipe with SponsorBlock. Is it the same thing or a different fork?