Headless Hackintosh M3-8100y

I've setup Catalina on M3-8100y. If I boot with HDMI monitor attached I'm able to access using VNC. If I boot without HDMI monitor attached, I'm not able to connect and VNC gives warning that resolution is zero. I'm wondering if this is a problem with LP detecting the resolution from the monitor and having issues when none is attached. I've seen some very old discussion on the forum headless setups but it doesn't seem that a solution was provided. Has anyone setup a headless Hackintosh?

Thanks!