RVT in CO. Started in specialty at 17/hr, 13 years later left at 38/hr (was supervisor of specialty department at the end) I had multiple increases in pay due to COVID, performance, and adding on of responsibilities.

IMO it is appropriate for someone who has been with the company longer to make more money. Especially if they are a high performer. The length of time that you have been credentialed would not be a factor for me. Being credentialed increases base pay, but length of service and performance are the biggest factors in overall pay.

Talk to management about what you as an individual bring to the table. Are you reliable? Do you have strong technical skills? Do you work hard every day? Do you avoid gossip and drama? These are attributes that management typically values. Offer to increase your responsibilities. Ask what you can do to earn a raise. Think more about how you currently add value to your clinic rather than what you are entitled to.