Refrigerator – lack of cooling capacity …. it is to milk mice

Hello together, maybe someone has a tip for me. My Dometic absorber fridge doesn’t really like to cool properly (whether gas or 230v) I’m just at the CP, outside temperature about 26 degrees, refrigerator temperature 12 degrees (frost compartment -14). Had fir run the time last weeks, at 10 degrees outside temperature it came to 2 degrees and frost compartment -20 degrees. I tried to convince the cooler even last week for better cooling : air guide plate installed, fan installed, the Kühli also turned upside down… unfortunately the cooling performance is still mau. Have also in the freezer the cooling plate outside, lead paste still looks good. Am now with my Latin at the end…. Gat someone else a tip? Greetings Al