This is what I ran which worked:
sudo apt install curl
but when running the command alone it does not work:
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Your curl isn't getting installed although the process is getting completed (look at the last 3 lines). The error code 403 as rightly pointed out in the comments, and thus either the server is down for maintenance or you're trying to access internet through a proxy that is not allowing you to do so. This is why it's showing curl not not found!