@ajroach42 SharePoint and Office Web Apps. I am not fucking with you; it really works, it's an older version of the OneDrive web apps, but it's self-hosted. I've got the 2013 versions of each on the same server coming from the toot. (2016 OWA might have brought it up to newer parity IIRC?)
I've tried the various ones for Own/NextCloud and they're all horribly janky, poor formatting, and excruciating to set up.