it depends on which embassy you will apply at, which you will find on their website, ie. the Paris Embassy takes around 4 weeks.
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When, as here, the OP doesn’t have a normal passport, the proces take longer time up to a couple of months.
So you are misinformt.
Here an example:
copenhagen.thaiembassy.org/en/publicservice/list-of-nationalities-that-required-additional-documents?