I have found many answers to this on another support page. They all work to some degree. One of them I would have never thought of until I the user posted why. Total facepalm 🏻♂.
For anybody else who wants all the madness to stop with their Apple Smart Keyboard capitalizing the first letter of a word. Be it because you’re trying to write a letter, you’re trying to type any of Apple’s words (iMac, iPad, iPhone, iPod, etc.), or you’re trying to type something as minute as an email address or username & password.
Here is a list of all the different ways you can get around the capitalization issue:
• Type the first letter twice (ie. Iipad)
• Turn off auto capitalization in Settings > General > Keyboard > Hardware Keyboard (not recommend)
• Press the Shift key before typing at the start of new line or sentence (you will be used to doing this when you use the on-screen keyboard)*
• *If you only ever use a lowercase letter for typing words that always start with a lowercase letter (ie. iPad), go to Settings > General > Keyboard > Hardware Keyboard and make sure auto correction is turned on. Then go to Settings > General > Text Replacement and create a text replacement for every word you can think of that always starts with a lowercase letter. By the way, it may be helpful if you search the web for a few good lists. I’ll help get you started:
https://en.wikipedia.org/wiki/Timeline_of_Apple_Inc._products
https://en.wikipedia.org/wiki/List_of_electronics_brands
* If it helps, I prefer to use the two latter methods together. It helps me with proper capitalization of brand names and I now know that the shift key will turn of the capitalization when it turns on by itself.