Help: very long html newsletter > pdf conversion

I am trying to help a small non-profit news organisation based in Zimbabwe. This is what we are trying to do. I know it's a bit unusual but there is an explaination of why we're doing this at the end if you want to know.

1.) We want to turn MailChimp HTML newsletters into pdfs to share via whatsapp. Here is an example if anyone wants to try: https://us6.campaign-archive.com/?u=d06b84a1d2f56ac8eecca6a96&id=708cdf966a - it's really, really long.

2.) If we use multiple pages the page breaks are in weird places. If we make it one long page it gets cut off because we hit the max page height limit.

QUESTION: is there any simple way to scale the newsletter to fit page height. I guess any height will do - if there are big margins we can crop it later.

QUESTION: Is there a way to create a pdf and manually insert page breaks in more natural places? Pages will then be different sizes but it will be easier to read.

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Why we are doing this: many people in Zimbabwe don't have reliable internet access or cannot afford to buy data. They therefore can't click "read more" links to full articles online, everything needs to be in one pdf they can view offline after they have downloaded it once. We are trying to keep file size around 700kb max for this reason too.