There's quite a bit of evidence to suggest that actually. It's also worth noting that the whole Sunflower Movement happened right as KMT were about to negotiate peaceful repatriation with the mainland.

NED has been working closely with DPP and with Tsai Ing-Wen in particular

*https://www.ned.org/remarks-prepared-by-national-endowment-for-democracy-president-carl-gershman-and-read-by-andrew-nathan-at-tecro-dinner-with-taiwan-president-tsai-ing-wen/

• https://www.ned.org/taiwan-president-tsai-ing-wen-honors-ned-human-rights-day/
• https://www.ned.org/taiwans-destiny/

Sunflower Movement leader Lin Fei-fan has documented associations with the NED as well

• https://www.taipeitimes.com/News/taiwan/archives/2013/03/02/2003556088
• http://web.archive.org/web/20140411235449/https://thediplomat.com/2014/04/sunflowers-end-occupation-of-taiwans-legislature/
• https://www.taiwannews.com.tw/en/news/3744833

Wikileaks also revealed DPP regular Reporting to AIT

• Wikileaks - TSAI ING-WEN COMMENTS ON DPP TURMOIL (2005): https://wikileaks.org/plusd/cables/05TAIPEI4870_a.html
• Wikileaks - DPP CHAIRPERSON TSAI ING-WEN ON CHALLENGES FACING PARTY AND U.S. ARMS SALES (2008): https://wikileaks.org/plusd/cables/08TAIPEI892_a.html
• Wikileaks - DIRECTOR'S FAREWELL CALL ON DPP CHAIR TSAI ING-WEN (2009): https://wikileaks.org/plusd/cables/09TAIPEI754_a.html

US has poured countless millions into shaping the opinions of the people in Taiwan through orgs like NED, it directly grooms US politicians such as Tsai Ing-Wen.