@beth_schlenker
Yes, there are other ways, but things get a little more difficult if you have already dragged some columns.
The default order in the gradebook is the order they appear on the assignments page. Rather than dragging them on the gradebook page, where drag / drop is the only technique, you can reorder them on the assignments page. You can drag / drop them there or there is an option to "move to" under the three vertical more dots to the right of each assignment.
If you use assignment groups (such as activities, homework, quizzes, etc.), then this technique limits you to ordering within assignment groups. If you drag to another assignment group, then you actually change the assignment group, which is probably not what you want.
Since you have already moved things in the gradebook, that becomes sticky and doesn't change things back when you drag them in the assignment groups unless you reset the sort order in the gradebook.
The How do I arrange columns in the Gradebook? lesson in the Canvas Instructor Guide explains more about changing the order. To get the gradebook to reset and match the assignment order, you would arrange by the default order and then click apply settings. If you have manually dragged columns, it will still say "default order", but it's more of a "default order with customizations". Clicking the "apply settings" will reset it to the default order that they appear in on the assignments page.
That lesson also potentially explains what you're seeing. If you have dragged columns in the gradebook, then when any new assignments are added to the gradebook, they are added to the end of the gradebook. That's a note in the Manually Arrange Columns section. It then adds that resetting the default view will put them where they need to be -- which strongly suggests ordering them on the assignments page rather than in the gradebook.
If you don't want them in assignment order, then you also have other pre-built sort orders such as assignment name, due date, point value, and modules.
If none of those completely match what you need, then manually dragging the columns around within the gradebook is necessary. If you have to do this, it works best when all of the assignments have already been created. Otherwise, new assignments go at the end and we're back to the same situation you're in now. You can reset them and lose any custom order or drag the new ones to where they belong.
My preference may not be your preference, but I arrange them in order within the assignments page in the order they appear but within each assignment group. I then use the default order in the gradebook. My wife does the same, but moves the total column to the beginning. Canvas provides a lot of flexibility here.
Also note that you can filter assignments. This makes the order they are in less important since I don't have to scroll through 190 columns (that's how many assignments one of my classes has) to find the one I want that is about 93 columns in.