EDIT:
Test it here
https://setfocusioskeyboard.bubbleapps.io/version-test
So I think I’ve figured it out. I had to resort to using javascript, so I can almost guarantee that someone who actually knows javascript can make a more elegant version of this, but hey if it works it works.
HOW TO KEEP iOS KEYBOARD ACTIVE/FOCUSED ON A TEXT FIELD IN BUBBLE:
To include javascript install the plugin called Toolbox. (I’m sure other javascript plugins work as well, have not checked)

Then to be able to connect javascript with bubble elements enable the ‘expose the option to add an ID attribute to HTML elements’ option in settings in the General tab.
The problem I was trying to solve was for a user to be able to add several items into a database without losing the iOS keyboard after saving each item. I used an input form, a button, and a repeating group with a text element to display the data. (DB is called ‘Steps’, the DB field the user is adding to is called ‘Action’.) It looks like this:
Add an ID Attribute for both the input form and another for the button. Call them whatever you want. Example:
Input form id:

Button id:

Then in the button’s workflow add ‘Run Javascript’
The javascript code I used:
var saveButton= document.getElementById("save_step");
var textInput= document.getElementById("input_step");
saveButton.onclick = function()
{if (textInput.value !="")
{textInput.value = ""; }
{
textInput.focus()
}
}
That’s it. Well almost. For whatever reason, it doesn’t work the first time the button is clicked, but does work on all subsequent clicks. Not wanting to explain this to my users I found a workaround:
Turn off visibility on page load for input form:

Then have the user click the ‘save’ button in order to display the text field.
Another workaround might work better in other apps, but in my case it really helps the UX feel native.
So there you have it. Hope this can be of use for more people.