I've done some research on some online dictionaries, whereby each dictionary provides exactly three dictionary definitions for the word "withal". But herein lies the rub: I do not fully comprehend the meanings of these three dictionary entries.
Take Lexico, for example:
with·al [wəˈT͟Hôl, wəˈTHôl]
- definition: in addition; as a further factor or consideration:
Example: "the whole is light and portable, and ornamental withal"
- definition: all the same; nevertheless (used when adding something that contrasts with a previous comment):
Example: "she gave him a grateful smile, but rueful withal"
- definition: with (used at the end of a clause):
Example: "we sat with little to nourish ourselves withal but vile water"
xbladefate25 I do not fully comprehend the meanings of these three dictionary entries.
The first two mean "too". The last one means "with", just as the definition says.