Is this a legitimate email?

Hello, today’s night I received and email from Dropbox that I think might be a prove someone hacked my account or maybe a phone(?). The title is saying “ NOTE: We recommend completing your Dropbox setup as soon as possible”
And under this is a message:
“ Your files are about to be ready to upload

Click below to see how easy it is to complete the Dropbox setup: you will have access to your files from anywhere.

Keep going

Do you have questions? Visit our help center for answers to frequently asked questions.”

This email is from no-reply@dropbox.com so it looks legit. Email was sent at 4:55 and it looks like someone checked some files from my account and wanted to download it and then Dropbox sent me this email. I’m not sure what to think about this because I didn’t touch my phone at this time, but when I did see this email, I took my laptop, downloaded Dropbox and started to downloading some files on it and I didn’t receive any messages like that one from earlier. Of course I changed my password and every time when I logged in to another device I got email saying that someone logged into my account (I didn’t receive message like this before).

I’m writing here because I wanted to make sure if I need to hard reset my device, or maybe this is something like a normal message reminding to me that I might want to do something with my files.
I’m not sure that’s important but my account wasn’t used in something about 5 years because I achieved limit for free space and just left it like this.