If you have lines on the screen when attempting to boot into recovery mode, then most likely you have a hardware issue of some sort.
If you have problems accessing recovery mode, then you can try a firmware "Revive" which resets the T2 security chip & firmware.
Revive or restore an Intel-based Mac using Apple Configurator - Apple Support
It would not surprise me that there is a hardware issue with the laptop since the 2019 models tend to have issues with their Logic Boards, plus they can also sometimes have issues with the built-in display. You could try using an external display to see if the lines appear there as well. However, it can sometimes be difficult to get video to an external display....especially before macOS begins to boot. Best to attempt using Clamshell Mode which requires the charger to be connected, along with an external display, and a wired USB keyboard & mouse, so when you close the lid of the laptop, it should force video to the external display. I find it best to power on the Mac and wait for the startup chime, then close the lid of the laptop immediately after the startup chime.