Colour banding and graphics issues in Catalina on UHD 620

i get colour banding in blur effects and gradients, plus HDMI hardly works except for once when it worked for some reason? plus, i get some ghosting from previous tabs/windows which also happened in windows. i have brightness and hardware acceleration working however, but I have seen a lot of others with the same issue

firstly, the colour banding no matter what, in catalina, i get colour banding on blur effects, gradients and other similar graphical effects. i didn't notice this happening in windows or linux, so it seems to be a graphics incompatibility or something.

the hdmi is a weird issue. i got it working once with a single monitor, but the same model (but separate) monitor didn't work. every other time ive plugged in hdmi, the external monitor goes black and my laptop screen builds up a vignette around the edge. when i unplug the hdmi, it inverts, making almost the whole monitor covered in black, and its not pixels, it seems to be something else, maybe the liquid in the display? not sure.

ive seen a lot of other people with the same issues with the same cpu/igpu but i haven't come across a consistent fix, other than replacing the screen with a better compatible one. however i looked through the compatible screens and it seems like this isn't a viable option for me, both because im not sure if it'd fix the issue and because of the price of a new panel.

the ghosting has always been present on my laptop, on every OS. it's consistent and happens whenever you switch tabs or switch to a different window. a ghost of the previous window will show until you switch back and forth or to a different window, but even that doesn't solve it sometimes. it's a very weird issue and i think it's something to do with the colour depth of my panel.

im running macOS 10.15.3 on clover. my laptop is a HP Pavilion 14-ce0502na with a i5 8250U, UHD 620 iGPU. the panel is 1080p, not sure of the exact model number but its around mid spec for my model of laptop.

here's some examples: https://cdn.discordapp.com/attachments/678025529194053654/679674254169866270/IMG_20200219_130045.jpg

https://cdn.discordapp.com/attachments/678025529194053654/679674253398114343/IMG_20200219_130205.jpg