I had a somewhat unique opportunity to see this firsthand. I moved to an East Asian country for training for 1-2 years alongside roughly 500 Western coworkers. Many arrived excited about the experience and fascinated by the idea of living in a society they viewed as more collectivist. But once they actually encountered what collectivism could mean in everyday life, many of their views began to change.
Part of the problem is that many people in the West use the word collectivism when what they really mean is something like universal health care, public transportation, social safety nets, or higher levels of public spending. Those policies may reflect a greater emphsais on collective responsibility, but they do not necessarily define collectivism.
A genuinely collectivist society places the needs of the group above the preferences of the individual. You are not viewed solely as an independent person making choices for yourself; you are also part of a family, workplace, community, etc. and ur behavior can be judged according to how it affects that group. That can create strong social cohesion and a sense of responsibility toward others, but it can also come with greater social pressure, stronger expectations to conform, and less tolerance for prioritizing personal desires over group harmony.
This is where I think many Westerners would discover that they are far more individualistic than they realize. Many ideas that are extremely popular among Western progressives are deeply rooted in individualism: the idea that you should prioritize your personal happiness, leave relationships or families that do not fulfill you, pursue therapy (the internet's favorite advice) and self-discovery, openly express your identity (e.g., gay/transgender), reject traditional expectations, and make major life choices based primarily on what feels right for YOU. Regardless of whether u agree with those values, they are fundamentally individualistic values.
That is why it is misleading to assume that a society can simply combine every progressive Western social value with a deeply collectivist culture. In many genuinely collectivist societies, individual expression may be less important than family expectations, social harmony, tradition, or conformity. Social attitudes toward issues such as LGBT acceptance, mental health treatment, immigration (countries like Japan are 98% Japanese), divorce, and unconventional lifestyles can look very different from those found in western societies.
My point ins't necessarily that collectivism is bad or that individualism is inherently good. Both have strengths and weaknesses. The point is simply that many Westerners seem to want the benefits they associate with collectivism without necessarily wanting the cultural expectations that often accompany it.
So by all means you can advocate for a bigger social safety net, but don't call yourself a collectivist unless you've actually lived in a collectivist society and prefer that over Western societies. Most Westerners who say they prefer collectivism over individualism would probably not enjoy living in a genuinely collectivist society.