Samsung has reportedly fixed the focusing problems that ailed the Galaxy S20 Ultra's 108MP main camera. Many users and reviewers found the 108MP camera's focus to be slower than the 12MP main camera on the Galaxy S20/S20+ (especially in lower light) and to occasionally miss altogether. The issues and reduced performance of the AF could be due to the 108MP sensor's lack of dual-pixel phase detect autofocus. Whether Samsung has added dual-pixel PDAF or has fixed the issue another way, typically reliable leakster IceUniverse reports the 108MP camera will focus just fine on the Galaxy Note20...
Source: https://www.gsmarena.com/samsung_galaxy_note20_wont_have_focusing_issues_will_use_sd865-news-43997.php