Not sure about my experience with the rheumatologist, is any of this unusual?

Hi, I was diagnosed with psoriasis and PsA just under two years ago, I'm in my 30s. Over those two years, I was started on methotrexate 15mg, it helped initially but then became ineffective after a few months. The rheumatologist then added sulfasalazine 500mg which didn't make much difference. Then, the methotrexate was increased to 20mg. This helped a lot but after a few months I started getting flare-ups nearly monthly. So far, so good. I used to have monthly blood tests which showed everything was fine. The problem began when my blood results showed my platelets were low (below the reference range, so was displayed in orange). The physician associate lowered my methotrexate dose to 15mg. This made my flare-ups really bad and increased its frequency to nearly biweekly. I had to have blood tests every 2 weeks too. I was on 15mg for around 5 months now and my recent blood test showed low RBCs and eGFR. I was concerned about the side effects and the ineffectiveness of methotrexate at 15mg. I contacted the physician associate, They said the eGFR is only slightly lower and said to continue taking meds as normal. I pointed out that 3 different blood parameters are now stated as low, but they said they'll refer me to haematology department. I argued politely, that at the therapeutic dose, methotrexate is causing issues, but at lower doses, it might not cause as much problems but it's not effective. I wanted to try different medications or a biologic. They said because my PsA score was 3/5, they cannot escalate to biologic. I told them I had frequent flare-ups, stiffness in the morning, stiff neck, etc but they kept saying during examinations they didn't see any major swelling. I'd like to know if anyone's been in similar situation; what other medication combinations you found helpful; what are some possible options; and should I approach private consultants to prescribe biologics and if so, am I then able to get it on NHS afterwards? Iv'e read some good reviews about biologics but my treatment has hit a brick wall and seems like I'm going to be on this barely effective treatment regime for a long time. They aren't willing to try anything different. Thank you in advance for any information.