I made the switch from web development to security a few years ago and initially took a 10-15% pay cut. I didn't get any certs and wouldn't necessarily recommend them. Instead, I joined various bug bounty programs to get practical (and resume-lite) experience.

Having implementation experience (via webdev) in addition to the bug bounty experience was a plus when I was interviewing.

If you're in a tech hub like SF or NYC there is plenty of security work. But, yeah, I would expect some kind of a paycut since you are moving from a (potentially) senior position to an entrylevel position.