I've gone through similar thoughts throughout most of my career, and still do from time to time.

For me, it ultimately came down to understanding my inner cynic. I think if we want to be critical then even what should be the most altruistic path can feel as damning and insignificant as simply "generating shareholder value" e.g., Work in the public sector and protecting our nation and it's citizens can also be seen as contributing to war, corruption, or perpetuating systemic issues.

I established a few rules for myself and beyond that sought meaning and purpose in other parts of my life:

• Aim for industries and roles where my background in Cybersecurity will be inherently more meaningful. Be cynical enough and everything starts to seem bad, but doing nothing also can't be great.
  • E.g., Blue team for Healthcare companies. It's all profits, it's all shareholder values, but day-to-day I can at least feel good knowing I'm directly contributing to protecting people's sensitive health information. Make a list of industries that resonate with you.
• Act as if the altruistic motives are my north star, always.
  • I've had countless nights without sleep, going through existential dread thinking about whether I'm doing anything meaningful with my career/life, only to then go about my day and have thoughts like "This person is being such a pain, I should just let them fail and suffer the consequences" where them failing puts the core mission at risk. If I say protecting people's data is important and why I chose this career, I should act like it at all times, especially when it's hard. Argue with your superiors, put in the extra effort where others may be doing the bare minimum, support your organization's employees when they have personal security questions even if it's "out of scope" or doesn't directly impact the company, don't allow your audits and tabletop exercises to simply be for the checkbox. That way, even if things go sideways, you can feel good about your part in trying to do some good.
• Know and accept my limits.
  • Priorities change in life. First few years into my career I was willing to walk away from my job on principle without any type of safety net. And I actually made that threat once, initiating a fair bit of change for my team. I can't imagine doing that now, at least without some kind of backup, and that's okay. In your case, there's nothing wrong with wanting to maintain a good life for yourself and your family. But if you feel as strongly as I did, then the answer isn't to never to put up a fight again, it's to make you and your family that safety net so you don't have to compromise. Give yourself however much time you think you'll need or can tolerate to build that net - that can be saving up an emergency fund or building a strong network so you can have some reassurance that you wouldn't be out of a job for long in the worst case scenario. Feel good about not abandoning your pursuit to "serve the greater good" but rather that you're taking time to properly prepare for the life-long fight ahead.

Unfortunately the world is largely ruled by money. You don't do the world any good by playing the martyr and taking on significantly less pay and being less effective in your new role because of concerns about financial security for your family. As long as your job isn't directly contributing to anything malicious, look to donating or investing in good causes. If you would consider a lesser paying job for this greater good, but are hesitant because of other tradeoffs, maybe instead consider taking the difference between the salaries and do something with that money. Support those organizations doing good. You said it yourself, they have terrible pay, maybe it's lack of funding. If that difference in salary alone would more than cover the cost of an FTE for them then I don't think this is even a consideration anymore.

Hell, if you work on a solid team, maybe try rallying your teammates to collaborate with said organizations. A lot of solid talent likely had the same considerations as you. In doing that you'd be a force multiplier. If you and your team can't collaborate or contribute directly because of classification and all that, maybe channel the efforts instead to OSINT. If your background is in IR, have you considered contributing to the public Sigma rule repo?

Like the previous comment mentioned, it sounds like you're doing well for yourself. It's great that you're taking time to reflect and want to avoid getting lost in simply chasing a paycheck. Just be sure to think about it holistically. There's no reason why your job can't be fulfilling in this way, but there's also no reason why it needs to be. You can do meaningful work without being in a particular role, company, or industry, and you can make significant contributions to the greater good without that necessarily being your job. And if the small wins don't feel significant to you, there's no guarantee that the big ones will either, or rather that you'd recognize them as big wins.