If it listed what it can’t do, it would be a very long document
Ah, but it does specify things the government can’t do. Most notably in the bill of rights. Madison famously objected to officially denying powers that weren’t enumerated in the first place. But there are issues that we think are too dang important to leave unsaid. Furthermore, there are denied powers in the articles before the amendments, as well. For instance, the government is not allowed to grant titles. Nor is it allowed to withhold habeas corpus except for times of civil unrest and/or invasion.
It denies the government things within powers already granted. For example Congress can lay and collect taxes (Article I Section 8) but it can’t lay direct taxes “...unless in Proportion to the Census or Enumeration herein before directed to be taken.” (Article 1 Section 9; although this particular part was done away with by the 16th Amendment).
Saying Habeas Corpus can’t be suspended unless in times of invasion or rebellion is more or less the same as granting the power to suspend Habeas Corpus ONLY in times of invasion and rebellion (which is telling the federal government what it CAN do).
I think we basically agree about the intent and ultimately the outcome is the same; the Constitution is definitely a limiting document.