In practical terms, drones can't respool their fiberoptic tether - in any dynamic environment, the fiber will at some point become entangled preventing it from being retracted. While there are prototype systems that use Power Over Fiber to keep a drone (and usually it's cable to prevent entangling) aloft indefinitely, all of those I'm aware of have an extremely limited weight capacity (far too little to support a decent optical setup) and aren't much of a concern.

Otherwise, a pursuit drone with an optical tether is a poor solution; it will leave fiber strewn behind it, the fiber is extremely vulnerable to accidental damage from something like a car or being wrapped around a sharp edge, has limited range and requires the base station to be static (so one could simply Hit Da Bricks their way out of a pursuit). There's also almost never a concern about wide area jamming in the civilian locales that these might be deployed in, so there's no real reason to use fiber instead of military style frequency-hopping radios.

That hypothetical microwave cannon would be an equal threat to both (if it exists), and if someone deploys a jammer to evade pursuit you can simply identify the epicenter of the disruption and follow them that way (something the FCC does regularly). And that's ignoring that there are AI-enhanced systems that can follow a target autonomously until the drone is able to reestablish a connection to the controller.

Honestly, birdshot and other drones are probably going to be the best counter to these systems.

I think you're assuming that fiberoptic isn't going to get caught on shit all the time.