Bloodwork data - Thyroid Issue

Hey !
Here is my latest blood data, my TSH seems high and I was looking for natural ideas to bring it down and make the thyroid work better.
I used to take T4 for 2-3 years and it dropped the TSH to 2.0 which was fine according to doc.

But I don’t want to take this crap all of my life so I stopped and am now looking at maybe balancing my diet with supplements (iodine,potassium?) to see for real what is my stock level.
The reason why I think this is a good idea is that I don’t have any antibodies or something that indicates a disease in the gland… Nor I have hypo in my family.

Na- Sodium (B) | 139 | mmol/l range 136 (---------------------) 146
Ca-Calcium (B) | 9.8 | mg/dl | 8.1 (---------------
------) 10.4
K+ Potassium (B) | 4.1 | mmol/l | 3.5 (-------*--------------) 5.1

Ferritin | 133 | ng/ml |
20 (----------*-----------) 250

TSH is 4.8

Folic Acid is low, B12 is normal. \

Symptoms of Hypo ? Nothing major… Training is going OK.

** T3 values will come soon… But I will mention that in previous tests 3-4 years ago, my FT3 was highest at a TSH of 5.8.
Even after taking 200MCg T4, my FT3 only went down a bit, despite TSH being much lower at 2.0.

This indicates a problem in converting T4 I would assume
Either way my FT3 has always been top third of the range, same for FT4. Strange that the TSH is so high.
Ideas ?