Raspberry Pi 4 -- Yes, You Can Use it for Web Development
It'll take a while for you to optimize your Pi 4, but the answer is a definitive "YES"--you can manage a development workflow on it. The real question is, do you want to?
Background
One of the big concerns with the Raspberry Pi 4 as a daily driver is, of course, whether the hardware can handle the comparable workload of a desktop computer. I've already touched lightly on overclocking the Pi and optimizing a boot disk. The final question is whether the little SBC actually has enough software support to be productive--in any effective sense.