"At least today I eat ice cream for dessert at lunch."
Translation:Măcar astăzi eu mănânc înghețată la desert la prânz.
I would consider them as synonyms. I am a native Romanian speaker and I use them depending on what word come to my mind first. Or you can consider "cel putin" as something like when you want to accentuate the fact that this is the only thing that makes you happy about the situation. Like in this sentence. But in the same time, "macar" can be used in the exact same situation. So yeah, I guess it depends on Duo. I consider them synonyms tho.