We're sorry about the trouble with Photoshop 2019. Would you mind telling us which macOS version are you working on? Please try updating Photoshop to the latest available version to check if that helps. If not, please try disabling the option to Use Graphics Processor from Photoshop by going to Preferences, then Performance. Once done, quit & relaunch Photoshop to check if that helps.
If the issue persists, you can try to reset the preferences of Photoshop using the steps mentioned here: https://adobe.ly/2Qzc0K3