Switching between Highlight and Underlining PDF in Files on iPad

When viewing a PDF saved to Files, what is the proper way to switch between highlighting and underlining text? I am using an iPad Pro 11", running fully updated 16.3.1.

On any given PDF in Files, I often need to quickly highlight one word and then underline something else. The existing workflow for doing so seems clunky and slow. I want to know if I am doing something wrong.

My current workflow for doing so is the following (assume the last thing I did was underline something):

• • Create Highlight: select word or phrase--> select Highlight-->select color of highlight==>word or phrase is now highlighted AND underlined
    • Remove Unwanted Underline: tap the word or phrase--> select Highlight-->select Underline==>word or phrase is now just highlighted
  • Create Underline: select word or phrase--> select Underline==>word or phrase is now highlighted AND underlined
    • Remove Unwanted Highlight: tap the word or phrase--> select Highlight-->select the color of the unwanted highlight==>word or phrase is now just underlined

Clearly this is a very slow, frustrating, and inefficient workflow. Either I am missing something, or this is a feature gap that desperately needs to be closed. Please let me know if there is a more efficient way to go about this without using a 3rd-party application. Thank you.