Frigidaire gallery not cooling

Seeking input and opinions.

2 months ago this fridge failed and I had an appliance repair service come out and they replaced the defrost thermostat. It worked fine for several weeks, then the fan started making an intermittent buzzing sound and today fridge and freezer are not cooling.

I can see visible ice build up around the air handler behind the ice maker which is in the top left corner of the fridge.

If a defrost restores normal function, is a repair with a kit (such as https://bens-appliances.com/products/5303918784-frigidaire-air-handler-housing-kit?\_pos=1&\_sid=a3f1919dd&\_ss=r) likely to work? Or is there more likely another underlying issue?

At what point are ongoing repairs worth it versus replace? The fridge came with the house and it is 7 years old. I see a new Frigidaire Gallery is a bit under $2k currently before taxes, etc. The first repair parts and labor was $525.

Thanks for any advice