Use the reports before you move on
You have just received several hours of specialist attention on your manuscript, for free. Even a rejecting report usually identifies real weaknesses, and the next journal's reviewers are drawn from the same community — they will likely see the same things.
Separate the reports into three groups: points that are correct and fixable, points that are correct but not fixable without new work, and points that are wrong. Address the first group before resubmitting. Decide whether the second group changes where the paper should go. Ignore the third, but check first that "wrong" does not really mean "unclear in the manuscript".
The failure mode here is emotional rather than technical. A paper sent to the next journal unchanged, days after rejection, usually collects the same criticisms again.
Reviewer reports from a rejecting journal are the cheapest expert feedback you will ever get. The next reviewers are drawn from the same pool.
Retarget deliberately
If the rejection was about fit, the new choice matters more than any edit. Look at where the papers you cite most were published, and at where work citing you appears — that is a better signal of your natural venue than any impact metric.
Be honest about level. Dropping from a leading journal to one immediately below it makes sense; dropping to a venue nobody in your field reads solves the acceptance problem and creates a visibility one.
Check indexing before you commit. A journal that accepts quickly but is not indexed where your discipline looks will make the paper effectively invisible, and if it is a predatory venue the damage extends past this one paper.
Rework for the new journal
Reformat properly — structure, section headings, reference style, word and figure limits. An editor who can tell at a glance that a manuscript was formatted for a different journal has already learned something about how carefully it was prepared.
Rewrite the cover letter from scratch. It should say why this paper belongs in this journal specifically, referring to work the journal has published. A generic letter is a wasted opportunity and a visible one.
Some journals invite you to declare prior review history and attach the previous reports with your responses. Where offered, this is often worth doing: it demonstrates the paper has been improved and can shorten the new review.