For sure, historical resentment of being conquered & "oppressed" by the Manchus is exacerbated by external actors. The Japanese were actually the first to do it, via their establishment of Manchukuo and persistent propaganda around Manchus (and thus the Qing) being colonizers of "China proper," which was of course incentivized by the self-interest of carving up China and was followed by various other attempts at "historiographical partitioning." The Koreans, and later the Taiwanese (DPP) and Vietnamese, joined in for their own benefits; and in the former cases they were also greatly influenced by the Imperial Japanese scholars during Japanese rule.
Western Sinologists initially opposed or ignored the Imperial Japanese narratives, because they were political enemies. But they gradually changed their tune as the CCP rose to power and supporting independence movements in China became a matter of strategic advantage. It has remained this way, ever since, and as the US-China competition has escalated, so has American efforts at "de-centralizing Chinese history" and subverting narratives of unity.
Internal forces within China have, without question, been influenced by these external actors, despite the Great Fire Wall and censorship. The fact is, the CCP never had an ethnic narrative or history for the "Han." Instead, "Han" ethnic narrative was prominent in the ROC as it played a pivotal role in the development of Chinese nationalism and the Xinhai Revolution, but the PRC never officially supported the narrative because it was orthodox Marxist-Leninist and borrowed the official Soviet line on nationalities. That is to say, "Han" exists mostly as a residual ethnic category under the PRC, there was no attempt at shaping narratives or defining traditions around it - it's just "who ever is not a minority, is Han."
Han "nationalists" emerged to fill this vacuum. In fact, most of them are not Han nationalists (in the sense of wanting to establish a Han specific state) at all, just people who were interested in having and providing their children with an identity that wasn't residual, because when your kid gets asked in school what it means to be Han, the answer shouldn't be "I don't know" or "it just means Chinese." The former creates psychological anxiety, while the latter threatens national unity. So Han somehow has to exist because people can't stand having no identity, and if they can't be Han then they'll just fall back to their regional identities (Cantonese, Shanghainese, Sichuanese, etc.) which is even worse for national unity.
Ultimately, the PRC's copying of the Soviet narrative on nationalities created this problem and ever since the Soviet Union fell in the 1990s, there has been a crisis of identity that is boiling beneath the surface. Han nationalists have risen to the challenge of solving this crisis through defining Han and transforming it into a concrete ethnic identity. The problem, however, is that because the identity of Han is so deeply tied to general Chinese history, it has an alienating effect towards minorities. If you simply equate "Han" with "Chinese" then where does that leave minorities? This is the root of the reason for why there are now constant conflicts in the Chinese online space over claiming ownership over specific dynasties and aspects of Chinese culture and civilization, which are in turn encouraged by external actors rejoicing at the opportunity to practice more divide & conquer.
What's the solution? Going out on a limb here, but the long-term solution here is to eliminate the Soviet concept of nationalities altogether. Everyone should have one identity - Chinese - and the historical narrative should focus on how this identity came to be. That was/is the concept behind Hua, but the problem is that Hua always existed in tension with the "56 nationalities" definition adopted by the PRC during its founding. Only by eliminating this tension can you create a country where everyone truly feels at home.