I clicked on New Item in My Content. I notice it was different after the update of 12-8-21. I tried to create a new feature layer using the 'Create Blank layer' option and it spun on 'Uploading feature service' forever. When I refreshed page it went to the detail page of new layer but under the Data tab it was empty and said "error'.
I also tried an esri template layer and chose Field Notes and got the same results. Nothing built.
Is this a fresh bug?
I tried the same workflow in AGOL and it worked for me. Could it be that maybe your browser? Maybe clear the cache? Or try another browser? Or simply reboot your PC? Sometimes a simple troubleshooting step can clear up issues.