Ah I've had similar
Had symptoms and family history that made rheumatoid arthritis be considered and GP spent most of the appointment telling me it was more than likely just tendonitis (despite having had the pain in symmetrical joints for about 5 months at that point) and very begrungily said they'd do blood tests...and she sent me to the physio.
Physio examined me and said in her opinion it did not seem like tendonitis and when she looked she told me that the GP had actually not even ordered the actual test for the rheumatoid factor and she told me when I had my bloods done to make sure the nurse added it on.
Not that it mattered because they all came back normal, although relevent to tell OP they told me they all came back normal...and then 2 days later left me a voicemail one came back later than the others and was abnormal and to take folate and be detected in 3 months.
When I returned to the GP cos my symptoms were no better and I had new symptoms including a skin condition, she told me that as my texts came back normal 6 months ago they had ruled out ANYTHING autoimmune and therefore would need no blood tests again.
And then told me it was most likely just anxiety and depression.
So I kind of then just sort of accepted it wasn't getting better and tried to be less stressed and just dealt with the pain (though apparently my pain is real enough to be prescribed naproxen on repeat?)
It got to a point where the skin sores ended up infected and I was starting to feel very very ill and and I ended up having a telephone appointment with a different doctor.
She contrary to the previous GP was that concerned she told me she wanted me to come in for a f2f appointment that same day and she also arranged for further blood tests to be done the same day as well. When she examined me she was quite shocked about how visibly bad and painful the sores were and asked me "why on earth didn't you come back sooner?! " So I told her about my last experience and she apologised and said she was sorry I felt like I couldn't come back for help, and please don't feel it ever has to get as bad as that to get help.
She admitted she didn't know if the skin issues and the pain issues were the same issue or 2 different issues but she assured me either way we will try to find out and treat it. She also used to be my main GP several years back when my mental health was at a very very bad point and she told me "I saw you a lot during that time and genuinely I do not think this is being caused by mental illness, there is something else going on and we will try to find out what" and also it was completely understandable that my mood was somewhat low as by that point I'd been dealing with pain, fatigue and a catalogue of symptoms and it wasn't surprising it was making me feel pretty shitty.
Unfortunately there are great GPs and there are perhaps not so great GPs,.and plenty in-between. Both the ones in my case were female and at the same GP surgery. But they treated me very very differently.
I can't say what the case is in the OP, it may have been a genuine oversight, everyone makes mistakes. But also know it is also possible that the GP had already made up their mind and really didn't care to order to test. None of us can say whi h it was.
I would however advise getting a second opinion.