After contacting my hosting provider and describing the problem and the System status notes, they changed max_execution_time to 120, php memory limit to 256MB and upload to 50MB. Just finished updating the theme no problem. Hope this helps. Cheers!

Trying to update from 8.1 to 9. I am expiriencing the same problem right now. Tried to update a couple of times, FTP wise, cPanel, deactivated plugins, erasing theme… same thing. The only option i have is to try and ask my provider to lift the memory alocation that is currently yellow in the System status tab (from 40 to min. 64) and max_execution_time (30 to 60). Everything else is green. I will post the result here, hope it will work.