Hello Alexis, I never used this MKR2UNO adapter (converter ?).
But, as I can see from the docs, it's just a form factor adapter. Since the MKRWAN1300 bar pins are the same as MKR1000 I see no problems.
Be careull using this kind of adapter, because voltages can be different. UNO normally uses 5V peripherals and MKR are 3.3V, and not 5V tolerant as a rule of thumb.
Also take care about the MKRWAN1300 version, because you'll need the no header version.
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Marcio Jr.