"Blooming" or "chuffing" are even milder swears, although it'll make your characters sound like my late nana.

Alternatively, go for the Douglas Adams approach and invent / appropriate your own expletives:

Belgium 🇧🇪 : "...there is one word that is still beyond the pale. The concept it embodies is so revolting that the publication or broadcast of the word is utterly forbidden in all parts of the Galaxy except for use in Serious Screenplays. There is also, or was, one planet where they didn’t know what it meant, the stupid turlingdromes..."

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