If China missed this opportunity, I guess they'll never be able to take taiwan by force ever.
The opportunity that you are referring to is very risky. China knows the consequences of starting a war in Taiwan. The US has vowed to defend Taiwan in the case of any attack from China which means unlike the case in Ukraine, the US will directly be involved in the war. Fighting the US is going to war with NATO and its allies which could signify a large-scale global war. From my observation, China is avoiding a confrontation with NATO that was why they never gave the needed military support. They kept disputing reports that they were supporting the invasion of Ukraine even when we all know that Putin and Xi Jinping are close friends. China will continue to do everything possible to influence the political structure of Taiwan and might not engage in any military confrontation.
NATO can't get involved there if it's China attacking taiwan. US may or may not get involved considering the nature of their commitment and the circumstances but NATO being an defensive alliance won't get activated unless the attack is directly to its members.
Article 5
“The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all and consequently they agree that, if such an armed attack occurs, each of them, in exercise of the right of individual or collective self-defence recognized by Article 51 of the Charter of the United Nations, will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area.
Any such armed attack and all measures taken as a result thereof shall immediately be reported to the Security Council. Such measures shall be terminated when the Security Council has taken the measures necessary to restore and maintain international peace and security.”
Article 6
“For the purpose of Article 5, an armed attack on one or more of the Parties is deemed to include an armed attack:
on the territory of any of the Parties in Europe or North America, on the Algerian Departments of France 2, on the territory of Turkey or on the Islands under the jurisdiction of any of the Parties in the North Atlantic area north of the Tropic of Cancer;
on the forces, vessels, or aircraft of any of the Parties, when in or over these territories or any other area in Europe in which occupation forces of any of the Parties were stationed on the date when the Treaty entered into force or the Mediterranean Sea or the North Atlantic area north of the Tropic of Cancer.”
Article 5 and 6 of the NATO charter makes it clear. Further NATO is mostly US and all of NATO are now overwhelmed with Ukranian and Middle east conflict where they are indirectly involved. If there's a case of war in Taiwan they may still get involved the same way.
I believe its unlikely for China to attack Taiwan (I might have said the same for Russian attacking Ukranians in 2022). Because China considers US the main opponent and the way they are trying to get over US is through science and technology. It's a common understanding in China that when they'll be rich and powerful enough, taiwan would peacefully join China. Till than, they don't want taiwan to declare independence.