Does my battery need servicing?

I’ve had my 13” MacBook Air since around August 2016 and it had been working perfectly until around last year or around whenever the Mojave update rolled out. At first, I noticed that my battery drained faster than normal (it used to last around 18 hours) and then I saw the “service battery” warning (from “normal” to “service battery”). I tried to reset the SMC, I still have plenty of storage left and my fans aren’t running excessively. As of today, my cycle count is only 483 out of the 1000 max cycle count listed on Apple’s support page. Nowadays, it only lasts around 5 hours and shuts down/sleeps at around 30%. Just today I noticed that I left it to charge overnight but the magsafe is still orange and the battery percentage is still only 81%. From what I’ve read from other websites, I could try recalibrating the battery or the problem could be linked to software bugs, glitches, etc. But before I give up and decide to take my computer to the store to get a new battery and a checkup, is there anything else I can do or try or any other explanations for my battery’s strange behavior?