I would never judge someones resume for staying at a job too long.
You can describe why you are looking for new opportunities, none of those will impact why you are sticking with your current opportunity. I was at my first job for 9 years. I enjoyed the people I worked with, learned a ton, and it afforded me a career pivot (ID->UX) that I would not have been able to make or afford by jumping to a new job as a Jr. UI designer.
The best advice I think I ever got was from Cooper Woodring at an IDSA conference very early on in my career was “Stay at a job until you stop learning”. As long as you can justifiably say you had been learning more year over year whether it was design skills, management skills, communication or leadership, theres no other reason why you would have to stay you stuck with a job IMO.