I got the M4 iPad Pro 11-inch when it first came out. For me, the 11-inch is the perfect size for air travel, household stuff, the right size for mounting in a car, emails, internet, and simple business stuff. But...a 13-inch would be a lot better for video editing, carrying across town for meetings that required the client to view video, etc.
The 11-inch seemed more conducive for personal and light business use, and air travel. The 13-inch I think is a better size for video editing, client meetings, cross-town travel to meetings, etc. YMMV.