https://us.community.samsung.com/t5/Legacy-S-Phones/Notes-app-Add-on-blocks-opening-the-Notes-app-on-Samsung-GS9/m-p/1387813/highlight/true
Solved: Re: Notes app Add-on blocks opening the Notes app... - Samsung Community - 1386137
Jan 7, 2021 - I didn't trust it either and I followed these instructions above and converted my notes in the settings and now I can access them. Thank - 1386137
add on blocksnotes app