I've been recording 4K video clips for almost 3 years using a Sony camcorder which saves to mp4 files.... editing on an HP Envy Windows 10 laptop (an Intel 4 core i7 CPU and 16 GB of RAM)….. and usually producing either HD1080 or 4k videos for viewing on vimeo.
My primary editing software is the 2012 version of Microsoft's Windows Movie Maker, saving to 4k videos using a custom quality profile. I've not run into any issues and have over 1,000 videos on vimeo.
Using and editing 4k files is about the same as with HD1080 files. Saving to 4K files makes for file sizes 4 times bigger than HD1080.... needing appropriately more local disc and online storage space, along with uploading time.