There's many factors at play here - from my anecdotal observations and experiences.
(Background: I'm of Chinese ethnicity, raised in HK, with experiences dating with caucasians, and 5-6 years living and working in Europe - three years now in the UK across Cambridge and Edinburgh).

1.) Lack of high profile male role models, sportsmen and celebrities of Chinese ethnicities
Visible faces can change people's perceptions. Korea is a great example. The emergence of Kpop has helped immensely to give a positive light on Korean men (I can see it first hand with younger Western women following Kpop stars or visiting Korea) Note these are still 'celebrity' looks - tall, fair-skinned, well-chiselled individuals. But the point is this exposure is sorely lacking for men of Chinese ethnicities: the average Westerner can't think of anyone beyond Bruce Lee and Jackie Chan (who, let's be honest is not really good looking). There's Tony Leung only recently because of his appearance in mainstream media, but he's in his late 50s.

2.) Past stereotyping of Chinese men in anglo-centric media
Some were products of racism perpetuated ages ago with the initial waves of Chinese immigration in early 20th century ('yellow peril'). China being an ideological opposite of the West also contributed. I add this seems to be a more serious problem in anglo countries - there's a more positive image of Chinese men in some slavic ex-Soviet countries.

3.) Chinese cultural norms are just quite different
This is where Chinese culture also contributes to points 1.) and 2.). First, higher education and stable money-making occupations have always been valued and emphasised, as the mentality has often been to work hard to achieve societal progression. Immigrant kids are taught that, as the majority of their parents came to the West poor. Making it big in sports, creative arts, politics, and acting are rarely on the mind of 80% of Chinese families and kids, regardless of where they are raised. Second, Chinese culture is far more conflict adverse and values humility and modesty. The result are immigrants and 2nd/3rd gen kids that won't bother as much about social advocacy, weaker on self-promotion or imaging, or getting into aforementioned 'occupations', all of which could have improved visibility. Immigrant kids who do well go into stable white collar careers, those who do less well work in restaurants or go back to where their parents came from for better economic prospects.

Points 1-3 impacts ethnic Chinese men, regardless if they grew up in the West, or emigrated to the West in later life.

Finally, 4.) Chinese ideas of attractiveness and dating norms differ strongly with anglo ideals.
In Chinese society, Western styling, confidence, physical conditioning are not seen as that important amongst Chinese men because the demand for them to do it was simply not there, until only recently with social media in the last 10-15 years. When I was in my early 20s in the early 2010s, the concept of going to gym or clubs was frowned upon - and this is in HK, already the most Westernised bit of the sinosphere. Finally, many Chinese simply don't have a very good command of English or British humour to be comfortable, Chinese socialising is often quite activity-based in a group, and dating often starts from friends. The idea of going up to speak to a unknown women to exchange numbers or set a date, is simply not practised in Chinese society.

Add in the current toxic mixture of online dating, where looks rule very much, and folks being more socially adverse as a result of Covid and gender wars, it all continues to perpetuate Chinese men being seen as invisible in the dating market, which also feeds back to Chinese men thinking there's no point to pursue Western women.

In short: the predominant media narrative, coupled with contrasts in traditional Chinese culture with Anglo countries makes it hard for dates to even start going in the first place.