What is the problem?
I have no idea on how to install octoprint 1.4 on my pi 4 with python 3 and can't find a guide either here or anywhere and since there's support for it I'd rather use python 3 than the eol python 2.7
What did you already try to solve it?
Tried changing the commands on Setting up OctoPrint on a Raspberry Pi running Raspbian from python/pip to python3/pip3
serial.log or output on terminal tab at a minimum, browser error console if UI issue ... no logs, no support!)
Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ... as much data as possible) 1.4.0, ender 5 pro, marlin 184.108.40.206, edge chromium, raspbian buster, windows 10, pi 4 4gb