I believe the Blue Prism answer to these kinds of issues is the insert/invoke Javascript functionality. As an example for using Insert Javascript Function and Invoke Javascript Function, try this:
Insert Javascript Function, Fragment: "function doSomething() { alert('hello'); Success = true; }"
Invoke Javascript Function, Function Name: "doSomething", Arguments: "[{}]" (an empty JSON array)
This does work for me, it displays an alert saying "hello". The challenge would be determining the javascript you need to run in order to manipulate the webpage correctly. I would recommend testing in your browser's dev tools before copying any code into Blue Prism; the errors that it gives related to javascript are not helpful.
On a side note, there is a library Microsoft released for .NET called
Playwright. I have found, when you need finer control than Blue Prism natively offers, it can be easier to run things through Playwright. There are a lot of upsides to it, but the downside is that it cannot interact with an existing browser, so you would not be able to mix and match it with Blue Prism functionality; just one or the other. (Also, I could not get the library to work within a Blue Prism code stage, so instead I have a network folder containing Playwright applications that I call from Blue Prism.)