It depends on which dialect of English you're referring to, but either is probably close enough, especially if you speak GA or can imitate it. If you can manage "Yoh keh" as in "moth fret" in General American English it's closer.
Japanese vowels can vary quite a lot, because there aren't nearly as many other vowels to confuse them with as there are in English.
The Japanese "o" vowel is usually close to [ɔ], the General American English CLOTH vowel (from Wikipedia: "cough, broth, cross, long, Boston", or "moth") or THOUGHT in either GA or British Received Pronunciation ("taught, sauce, hawk, jaw, broad") than to GOAT in either dialect ("soap, joke, home, know, so, roll", or "show").
The Japanese "e" vowel is usually close to [ɛ], which is the General American English DRESS vowel (from Wikipedia: "step, neck, edge, shelf, friend, ready", to which we might add "fret") than to [e] or [ej] or [eɪ] or [ei], which is more like the General American English FACE vowel ("tape, cake, raid, veil, steak, day", to which we might add "slay"). RP doesn't have [ɛ] at all; the closest it has is that it realizes SQUARE ("care, fair, pear, where, scarce, vary") as [ɛə].
Other English dialects (AAVE, Irish, Scottish, Cajun, Southern American, Jamaican, Standard Indian, Bangladeshi, Nigerian, Australian) realize these vowels in their own different ways which may or may not correspond well to the Japanese phonemes you're asking about.
Or "yoh keh" as in "moth fret"
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I pronounce pokémon as "Poh Key Mon". Which is a third variation to "ké"