the system update for galaxy s10+ turned my screen black & white & changed my font.
I restarted my phone, changed the theme, checked a the normal functions (night mode, wind down, battery save,) that would have done it.
When I restarted it, it was color for a few seconds and then reverted back.
Let's bring back the color and get your screen working again! Please restart the phone into Safe Mode and see if the performance changes which will indicate a 3rd party app may be affecting the phone. https://www.verizonwireless.com/support/knowledge-base-223011/ YaleK_VZW