The format function seems to have missing an options parameter.
current format() definition on index.d.ts
format(template?:string): string
result

workaround
// @ts-ignore
return dayjs(dateString).format(format, { timeZone });
When using dayjs-ext I don't want to type // @ts-ignore on my code.
Would it be possible to add an options to format() definition on index.d.ts?