This whole response is being written using slide to type, and it definitely adds spaces after each word.

Maybe you’re unaware that it will leave the cursor at the end of the word, with no space, which indicates that if you backspace it will delete the whole word, or replace it in full with one from the predictive word list above the keyboard if it got it wrong. If you keep typing it adds a space automatically.

Generally one picks up their finger between words, but different autosuggest logic applies when swiping versus pecking, on both iOS and Android. The keyboard will dynamically adjust the probability of suggesting next words and how easy it is to swipe given words. Generally, it will work against you with technical writing that isn't predictable small talk.