I'm from Finland and I've done both native and English. My original idea was to do 50% Finnish 50% English as that was the way my life was at the time (I'm a daily vlogger). However, since doing subtitles was a pain and most views were local, I switched to Finnish after maybe 10 videos.
However, I made some "broader topic" videos like reviews on boring days in English, and one of the videos picked up steam, so I switched to English. Vlogged in English for almost a year until I noticed my vlogs were still mainly getting views from Finland, so I switched back to Finnish.
But then I lost quite a few subscribers who didn't like me using Finnish. As I've also felt more at home speaking English I settled with English once and for all at the start of this year.
I get excited easily and speak really fast, and I've noticed that when I speak in English it slows me down just a tiny bit enough to make it more watchable. However, I kicked of a travel channel in Finnish few weeks ago (even when vlogging in English I also shot Finnish footage on trips) since my mom likes to watch my travel videos and her english is bad.