I agree/Acknowledgement option in Rise 360

Personally I use a combination of a single item Checkbox List followed by a Continue button with the 'Complete Block Directly Above' completion criteria. This interaction isn't recorded by the LMS, but learners have to check the box in order to continue – assuming navigation is Restricted, as is typically the case – so acknowledgment is implicit in them progressing the module. The two-step process makes it less likely to be absentmindedly clicked through.

If you absolutely need an explicit record, you could embed a Storyline block that's essentially an agreement button and tie course completion to that. I'm not sure that's less clunky than using the built-in Knowledge Checks, but it should work so long as you're asking for confirmation at the end of the course so that it isn't marked as complete prematurely.

Another alternative is that you could embed an external survey. I've only used this for modules that don't sit on an LMS as a means of gathering feedback, but I suppose it's possible you could match a form response to a specific learner. Whether you could automate that process likely comes down to the LMS you're using.

I know my initial suggestion isn't perfect but you can probably see why it's the solution I settled for.