Thank you. I fixed the black screen problem as you said: In the settings, I went to the list of apps that use iCloud, disabled the switch next to Obsidian and then re-enabled it.
I’m uploading the black screen and solution video here in case anyone else has this problem.
But the sync thing seemed too complicated and it doesn’t work as smoothly as Logseq. Folders hang separately on their own. It doesn’t look organized like a single database. Maybe I can try to use it again later.