I guess it depends on your circumstances. In Europe, for instance, the cost of a degree is sometimes quite low. My gateway from tech to law was a part-time masters degree in political science, and which cost around 200 euros a semester (in Germany). That degree gave me enough experience to then apply for a PhD in law.
Which brings me to the next point. Doing a law degree and passing the bar is perhaps the obvious path to doing policy things. It’s basically the only way that you can end up actively participating in courts, for example. But there are many other options! For myself, the plan is to stay in academia and not take any bar courses (then again, who knows what will happen!). Academics have lots of potential to shift policy, especially as neutral agents who aren’t paid by either side of particular debates. Our papers are read by policymakers and judges, who often don’t have the time or resources to think deeply about particularly gnarly topics. But there are lots of other options which could also work, and I guess finding a "niche" would depend on your specific circumstances, connections and skillset.
If you’re looking to spend more time thinking about policy issues, I’d start by simply sleuthing online. Bruce Schneier, for example, regularly writes excellent pieces at the intersection of technology and policy, which are very well hyperlinked to other high quality stuff. These kinds of blogs are a great way to get into the space, as well as to learn about opportunities which are coming up. Reading journal articles that sound interesting is a good option too (and US law journal articles are often quite accessible). There are also spaces offline, such as conferences which encourage both law and tech people (there’s one happening in Brussels soon [1]), or even institutions set up specifically to operate in this space and which have in-person events (Newspeak House comes to mind [2]).
[1] https://www.article19.org/digital-markets-act-enforcement/
[2] https://newspeak.house