... the only way you can get a raise is to change jobs.
This is not strictly always true. If the company you are working for is doing well and isn't in the business of cutting for the sake of cutting, then you CAN get a raise if you can articulate the accomplishments and value you add AND (this is important so pay attention) you _ask_ for a raise.
If any one piece of that chain isn't true, your chance of getting a raise is slim. You actually have to accomplish some things and add value. You DO need to be able to explain them and why they add value. Example: "I added new automation which saves us 20 man hours per week. This has allowed us to be more productive and save the company money." You must remember that this isn't a game where everyone gets a trophy just for competing. This is the real world where if you want to be shown you are valued more, you need to add more value. Just showing up isn't enough.
The whole asking part is an art that few possess. You need to be prepared for what happens if they say no and how you will react both immediately and in the days afterwards. It wouldn't hurt to have other job opportunities you're pursuing in mind. If you can have an offer in hand, then that's even better because you're negotiating from a position of power.
This is a game of chess, so don't play checkers. Changing jobs for raises is not a good long term plan to do frequently.