Now explain why government raise the debt limit? other than allowing printing to get fiat money?

Ah yeah, that's a common misconception.

Deficit spending doesn't create new money. Deficit spending borrows existing money from the population and institutions in exchange for a promise of future government revenues. The Fed does not participate in treasury primary auctions and does not monetize the debt as a means of funding government operations.

If you printed new money to pay for the government, you wouldn't have a debt. That's double-counting. Not to mention the debt is twice as large as the entire money supply so what you're suggesting isn't even physically possible. It would be inflationary to simply print new money to finance spending, which is exactly why it's not done.

[edit] Also the debt limit is a stupid concept that's likely unconstitutional. Congress authorizes spending, meaningful debate over paying for it by adjusting the debt limit likely falls afoul of the 14th amendment's public debt clause. But yeah I mean the debt limit goes up because the government spends more money than it takes in, so it needs to borrow more each year.