Obviously, I haven’t tried it yet as they are unavailable still. However, as @jonathon said, “Should be fine. It’s a Pi4 underneath.” Only better, as the 400’s cores run at 1.8 Ghz compared to the RPi4b at 1.5 Gz.
Here’s a link to where a dude completely tears down a RPi 400.
EDIT:
Two accessories you might want to consider purchasing.
A short micro HDMI to HDMI Adaptor.
With this, I leave the adapter on the RPi4 and just connect the regular HDMI connector to it. That way, one is not changing out HDMI cables all the time.
A USB to micro SD and/or SD adaptor.
You will need one of these if you want to install software on a micro SD card, such as EndeavourOS Arm.
Pudge