Your score, resolved tickets, badges and certificates are one running total on your account. There is no reset button for them.
Why a reset would break the certificate
Certificates are checked by other people against a public verification page, which shows the ticket count the credential was earned on. A count that the holder can reset is a count nobody can trust, so progress only goes forward here.
That leaves the question worth answering: which of these did you want a reset for?
You want harder or different tickets
A high score does not mean the queue has run out. What usually prompts this is a queue full of the same few categories, and Training Focus is the control for it: open Settings, then Preferences. Pick the categories you want and the queue narrows to them. It is available on Pro, teacher and classroom accounts.
Analytics shows Category Breakdown, which is the honest view of what you have been avoiding. Reading that and then setting Training Focus against it changes what you get far more than a reset would.
You want a clean leaderboard
A class leaderboard already works this way. It counts points since joining, from a baseline taken the moment you joined, so a student with months of play does not start a new class at the top. Joining a class gives you the fresh comparison without touching anything you have earned.
You want the practice back
Past tickets stay readable rather than disappearing. Open Past Tickets from the profile menu to reopen one and read what you did, including the solution steps and the explanation.
Tickets repeat on their own as you play, so a scenario you fumbled a month ago comes around again. There is no need to clear anything for that to happen.
You want the account gone
Deleting the account is the one thing that removes everything: progress, certificates and the account itself, permanently. The steps are in Delete your account. You can sign up again afterwards with the same address, and you start from nothing, including any certificate you had earned.
If you are on Pro, cancel the subscription first so the billing stops. See Manage or cancel your subscription.
Teachers
A classroom is scored on its own term. The leaderboard counts points since joining, so a class starts level even when one student has been playing for months, and that is the reset most teachers are actually after. A student’s lifetime count stays where it is, because their certificate is derived from it.