Hi @jfridell ,
I have had a hunt around and I have been unable to find any feature that would enable this out of the box. I hunted around the community and found a few historical feature requests that relate including https://community.canvaslms.com/ideas/5300 and https://community.canvaslms.com/ideas/8225 (which the second one I thought may be a work around).
I did think of a bit of a workaround which may benefit. If you created an LTI tool to 'Check Course Enrolment Status' (i.e. one that would be shown to all users) you could have the same benefit (you could even do this with a simple redirect). So rather than restricting it only to users who need to complete their enrolment, you could show it to all users and make it slightly more general. I think this would still have a 'call to action' for those users to check their enrolment and then you could guide them through completing.
As a bonus, then all your other users also have a mechanism to ensure their enrolment is correct. I do realise this is not ideal, however, with the current functionality, is the best I could recommend.
Hope that helps!
Stuart