Any employer who retaliates is not worth working for anyway!
You're likely to get a raise without asking in most companies. The bureaucratic levels system is designed as a counter to people forcing salaries beyond their ability. But like someone said, you know your team better than us.
"one of the only people" implies that you are not alone with the extensive knowledge. If they fired you could they still continue? Are the management even smart enough to know how much they don't know? or how vulnerable they are?
I have had many bad experiences with managers who could consider your demands for a raise as a form of ransom. Consider @jerryu's suggestion.
I once wrote about this, and FWIW, a few people have found it interesting
https://stonecharioteer.com/posts/2022/two-of-three-rule.htm...
My two are: people and pay. When pay begins to feel like it sucks, it usually means I'm fed up of the people.
Not sure if you are in tech, but if you are, the tech job market is at an interesting point right now. Cost of labor is likely going to be trending down as companies stop paying top % for engineers, FAANG stops hoarding talent, and more people enter the job market from layoffs.
If you are able to shop around for a job and get a few offers, that will put you in a better position to negotiate. Just be ok jumping to one of those offers if you don’t get the raise.
- search for another job
- be confident about 1 or 2 offers (maybe even go ahead and do a couple of interviews to be even more confident about your chances to switch jobs)
- ask for a raise as you would usually do (you don't need to mention you may switch jobs)
Deserve is not the same as need, or want though.