Hey Callum, if I were you I’d rather set up a brand new table with one record per day and use Airtable’s in-built grid function:

And you’d end up with something like this:
Table:

Email:

Setting up HTML properly in an email is going to be a pretty big undertaking; you’re going to have to think about how it looks on various screen sizes, how different email clients handle it, etc, and so it’s really much easier to offload that work to a service that already handles it
Best of luck either way man, and hopefully someone else is able to offer you some advice about the HTML stuff
@Callum_Green
Unfortunately, Airtable's "Send Email" action does not support all HTML/markdown tags, and it doesn’t properly format the HTML/markdown tags that it does support.
In fact, even normal plain text is not formatted properly by Airtable — you’ll notice that Airtable will replace all line breaks with paragraph breaks.
All of these email problems exist because Airtable is trying to inject its own invisible HTML code into your email that you can’t see nor remove.
If you’d like to use your own HTML code for sending your automated emails, I would highly recommend automating the sending of your emails by using Make's advanced automations & integrations for Airtable, which properly respects all HTML code. Make doesn’t try to inject any of its own code which would mess up your own code.
And not only does Make allow you to type up your own HTML code, but Make also offers a lot of advanced HTML features such as a "table aggregator", which lets you aggregate multiple Airtable records into one HTML table that you can format with HTML tags however you'd like.
If you’ve never used Make before, I’ve assembled a bunch of Make training resources in this thread. For example, here is how you would instantly trigger a Make automation from Airtable.
I also give live demonstrations of how to use Make in many of my Airtable podcast appearances here. For example, in this video, I show how to work with Airtable arrays in Make.
p.s. If you have a budget for your project and you’d like to hire an expert Airtable consultant to help you with any of this, please feel free to contact me through my website: Airtable consulting — ScottWorld