To clarify this, there are several different kinds of rate limits. Most of them expire automatically (and can’t be changed by Let’s Encrypt staff). However, one special rate limit (called “ridiculously excessive traffic”) does not expire automatically and requires intervention by Let’s Encrypt staff, which must be requested on the forum.
It can be confusing because people sometimes ask about both kinds on the forum, which might lead to the impression that all rate limits need a request here. But if the rate limit in question is any kind other than “ridiculously excessive traffic”, it’s not useful to request a response here because the staff can’t change the other limits.
It seems from @JuergenAuer’s and @cpu’s responses that the limit is not one that the staff can change, but is one that resets out automatically within a week.