Amid the usual barrage of new launches around this time of year from the likes of Samsung and Xiaomi, I’ve been checking out the highest-end device yet from a manufacturer many readers won’t have heard of—but it’s one that marks an unusual collaboration with another brand that might be more familiar. Infinix is a sub-brand of Chinese company Transsion, which also owns the smartphone maker Tecno. The manufacturer is particularly successful in developing smartphone markets like Africa and the Middle East; across all of its brands, Transsion accounts for about half of Africa’s smartphone market share, according to figures from Canalys last year. Infinix largely targets young consumers in the markets where it operates. Its ultra-popular Hot series is designed to be affordable and stylish, while the Note is a step up in performance and functionality. The new Note 60 Ultra, however, is Infinix’s first attempt to compete in truly premium terms.…