Defense spending, China's position in the Asia-Pacific region and lessons from Ukraine were just some of the topics dominating the IISS Shangri-La Dialogue this year.

The summit sees top world leaders, defense officials and key executives gathering in Singapore from May 29 to 31.

Here are some of our key takeaways:

Countries appear to have generally accepted the premise that they'll need to spend more on their own defense. Nations like Japan, the Philippines and the Netherlands are planning increases in allocations there.

U.S. Secretary of War Pete Hegseth said in his remarks Saturday that countries should be spending at least 3.5% of their GDP on defense. Even the likes of New Zealand, which falls below the 3.5% mark, is boosting its spending in that area.U.S. President Donald Trump has pressed the idea for years and was initially met with consternation from many countries. Now many of them are embracing it, at least publicly. Dutch deputy prime minister Dilan Yesilgoz-Zegerius even said the U.S. is "right" to ask countries to spend more – noting that Russia's invasion of Ukraine changed the calculus in that direction for the Dutch public.

"No one country can do it all alone," said Gen. Jennie Carignan, chief of the defense staff of Canada. "Having the ability to get together to complement each other's capabilities is incredibly important," she said, "but in order to do that, you have to have your own defense."

Even before the summit actually kicked off, much was made about how China would not send its defense minister to the forum for a second straight year.

Beijing's delegation was led by Major General Meng Xiangqing from the People's Liberation Army National Defence University.

Dong Jun's absence was noticeably felt, with Hegseth saying: "I wish my counterpart was here at this conference, but I look forward to other options when we can cross paths and ​communicate."

Japan's defense minister Shinjiro Koizumi said he was "feeling sad" that Dong was not at the conference and urged more dialogue with Beijing.

Others, like German chief of defense General Carsten Breuer, said that China is losing a chance at dialogue by not having a ministerial-level delegation.

The Philippines took an openly dismissive stance, with national defense minister Gilberto Teodoro telling CNBC that "as a value proposition their [China's] presence here is reduced to a minimum ... which is to promote the party line rather than to engage constructively, so insofar as I'm concerned, it's no major loss for me."

But a lower-level delegation did not stop the Chinese delegates from defending their positions with vigor.

During his session at the Dialogue, Meng took aim at Japan's defense spending hikes and expansion of weapon sales, asking if countries in Asia will trust Tokyo remilitarizing after its actions in World War II.

Even former officials in the delegation were strident, like former vice minister of foreign affairs Cui Tiankai, who maintained Beijing's position that cross-strait tensions were a matter of territorial integrity and national unity for China.

"No one cares more about stability in Taiwan Strait than we in China, because on both sides of the Taiwan Strait it's Chinese territory."

It was not a one way street, however. Japan's Koizumi accused the Chinese of a "lack of transparency" in their military buildup, and the U.S.' Hegseth warned Beijing there was "rightful alarm" in the Asia-Pacific region regarding China's military buildup.

Manila's Teodoro struck the most combative tone, saying that China expansionism continues unabated. "They're unrepentant with their expansionism and unrelenting, and to deny that would be to be absolutely dishonest," he said.

Ukraine still resonates strongly within the international community, and the methods of war being used are being eyed by all countries as Ukraine fights off the invasion from bigger, better-resourced Russia. That concept of "asymmetric warfare" has reshaped defense strategy globally."There's a very keen interest in lessons from Ukraine and around Ukraine, it's a kind of understanding that first asymmetric deterrence and asymmetric fighting is something which matters," Pavlo Klimkin, a former Ukrainian foreign minister, told CNBC in an interview."What is at stake in this war is the whole sense of security -- whether we have or we don't have any security architecture in Europe and around Europe, where Ukraine belongs to, and how to fix it within the future security architecture," Klimkin said.

Countries like the Philippines are eyeing Ukraine's tactics as they boost defense spending – and Dutch chief of defense General Onno Eichelsheim said they actually have Ukrainian advisers working with them to assess what's useful – and not – to allocate resources to.