Have you tried the Kweb browser? I don't know what your definition of slow is, but by my standards it is decent even on the Raspberry Pi 1B.
I feel like we have something to look forwards to in terms of browsers as well. The vc4 driver is still in the works but it is maturing. It will provide OpenGL 2.1 to the Pi. A GPU focused webengine called Servo is currently being developed by Mozilla, with planned support for OpenGL 2.1. It sounds like the Mozilla plan is to rework Firefox to use Servo.
In theory; what should happen is the vc4 driver will develop all of the closed driver capabilities, become the default driver, and all Raspberry Pis will become OpenGL 2.1 enabled by default. Firefox will switch over to Servo and become truly GPU accelerated, with its hardware acceleration supported on Raspberry Pis.
Then you and I should be able to have a fantastic web experience even on a Raspberry Pi 1B, even better than with Kweb - which is already pretty decent.