P2421DC, PC VGA to monitor HDMI or DP not working

I would like to connect the VGA video output of my computer either to a Dell P2421DC or P2418D monitor. The computer has two video outputs that works fine simultaneously, because I've been able to connect other monitors using direct HDMI to HDMI and VGA to VGA connections. However, I have not been able to get any VGA to HDMI or VGA to DP cable/converter/adapter that I have tried so far to work? From what I have read it is a common problem when there are two video outputs from the computer and DELL monitors are used? Do you have any connector that can fix this? Or any possible solution? Note that my computer has not USB-C video output, what would have been other possible solution for this monitor.