I'm wondering if I can do this in the MK3 or the plus, easily create a new clip and choose the
pattern content that makes it up.
Yes, well... sort of, depends... In the SW you can just right-click a Pattern and convert it:
Now from hardware (or M+) I am not aware of a way to convert a single Pattern, we can only convert all Patterns in a Section in the Song Mode Menu, the 3rd top button is to Convert to Clip.... I guess you can use that and then delete the extra Clips or create a Section with only the Pattern you cant to convert 1st - Not very practical unfortunately unless I am missing something.
Convert
It's very odd to have a way to convert every Pattern in a Section but not a single Pattern on the HW. 🤷♂️
It's so easy in the software. Hopefully it'll come within a future update. It would add to ease of use in the clips and section views tremendously!