Yes indeed! Cord length is actually technically limited to 25 feet by NEC (though one wonders if NEC applies to a plug in device like a UMC since it is not hardwired.
2017 NFPA 70 (NEC) Article 625.17 (C) says:
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But to expand on the extension cord comment: I would just about never recommend charging an EV on an extension cord at your primary home location. I might in special circumstances charge on an extension cord when on a trip somewhere, but I would watch it like a hawk and try to avoid using it while sleeping.
I would absolutely have a receptacle added or relocated to be where you need it.
Can you explain a bit more about the situation you are trying to solve for? Likely moving an existing receptacle or adding a new circuit would provide a safer and more convenient solution. Something like a Wall Connector might also be interesting rather than a cord and plug connected device like the UMC.