I have the same problem. I got three times the same type of email, as yours:
The usual email notification:
"Thank you for your interest in joining Upwork. We have reviewed your application to join, and regret to inform you that we are unable to accept your Upwork freelancer registration at this time. Please do not consider this a reflection of your abilities – while we would like to offer every qualified freelancer a spot, admission is highly competitive as Upwork receives more than ...."
I wrote all what I did and I completed all the parts with skills, experiences and some samples of my portfolio.
I have had your same thought: Maybe my account is rejected automatically by automated bot after 24h?
Mine also less than 24h, unfortunately
I checked me too in the "search profile" to find people from my same country with my skills and I haven't found so many pro in my field.
I'd like to have a help and advice cos I don't know what I can add more than I have already written or added