Do you need a capital letter after ellipsis if the sentence is
“ we’ll check later.”

If you are using it to start a new sentance, then yes you can, if not then you don't need to

Explanation:

https://english.stackexchange.com/questions/73524/should-a-capital-letter-be-used-after-an-ellipsis#targetText=If%20so%2C%20what%20follows%20is,the%20sentence%20without%20a%20capital.

This website says what I said up top. "If so, what follows is a new sentence, and it starts with a capital letter.  If you think the ellipsis represents a delay within an as-yet-incomplete sentence, but you've decided you don't want indicate that delay using some other punctuation (comma, semicolon, etc.), then just continue the sentence without a capital."

Hope this helps! :)