There's a bit of a smorgasbord of mistaken assumptions here, so let's go through them slowly.

1. 'New Qing' historians

Do not exist as a homogeneous collective. While I think it's fair to refer to a 'New Qing' turn, characterised by a focus on Inner Asian dimensions of the Qing and broadly global Early Modern parallels, individual historians have wildly differing views.

2. The Qing not being considered 'Chinese'

Attitudes towards whether to use 'China' as a term encompassing the Qing vary. However, the critical issue is not necessarily that 'China' is a fundamentally inappropriate term to use, but rather that it is an English exonym that gets applied to a variety of contexts and thus carries a variety of baggage. It is valid to call the Qing Empire 'China' insofar as one may wish to argue that the two ideas were, during the Qing period itself, synonymous. However, the Great Qing was not 'China' in the same way that the Great Ming was 'China', or how the Republic of China was 'China' or how the People's Republic of China is 'China'.

3. Vast majority of human lived experiences were [Han] Chinese

This implies for one that the experiences of minorities are irrelevant to any sort of 'grand narrative', and that no state established by a minority can claim to be anything other than representative of its majority, whatever its internal power structures may be, or the self-identification of its rulers. Arguably only with states in China has there been so fervent an insistence upon the notion of ruler acculturation – we do not call the Mongol Empire the Turkic Empire, or the Seleukid Empire the Syrian Empire, or the Mughal Empire the [North] Indian Empire. We don't insist that the Kingdom of England under William I was a fundamentally 'Anglo-Saxon' state without Norman characteristics: indeed, it was once a popular image that the idealised pure 'English' lived under a 'Norman Yoke' for much of the medieval period!

4. Elitist focus of historiography

Far from it – the modern approach has been to actively rediscover the perspectives of Qing subject peoples who are, in the modern PRC and many of its neighbours, minorities with limited political enfranchisement, rather than the traditional focus on the viewpoints of Han Chinese elites.

5. Only Han are considered 'Chinese'

Sort of but not entirely: 'Chinese' is so often a shorthand for Han Chinese that the use of the term 'Chinese' can be highly misleading and imply a Han-centrism to the idea. Only Han are considered Han Chinese, which is a different prospect from the idea of a 'Chinese' national construction that may be inclusive of (albeit in arguably cynical ways) non-Han peoples.

6. dulimbai gurun i niyalma

The phrase dulimbai gurun is one that is often misconstrued, and I would direct you towards this thread on this subreddit and this discussion I had on r/ClassicalChinese with /u/10thousand_stars. The Treaty of Nerchinsk is also a difficult text to use too much of because it is arguably one of the only texts in the relatively early Qing to consistently use dulimbai gurun in any systematic way, which is arguably for two reasons: firstly, that it was a term of convenience for ease of communication with the Russians, and secondly, that the Manchu and Russian versions of the treaty were derivations of a common version in Latin, for which acceptable compromises had to be made. Finally, the one use of dulimbai gurun i niyalma to refer to the Mongols at Nerchinsk is not a huge amount to go off, and there is not one particular correct reading: while one option is to say that 'people of the central state' means 'Chinese people', it is also viable to interpret as 'people within the sphere of influence of the Qing' or 'people under Qing protection' or indeed 'people of the Qing', considering that a translation of dulimbai gurun as simply 'China' is based on a tendentious, decontextualised reading of the term.