They make one that screws into the lamp base, has two (ungrounded) plugs, and has another lamp base so you aren’t losing the bulb. It’s really not at all hard to put together. Much cheaper than a generator and you won’t have to carry it around.
https://www.amazon.com/dp/B08PKMXP8R?ref_=cm_sw_r_cp_ud_dp_06Z6GBJESPJBA2CKATDJ
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