Matt
Well, you mention "organic" a lot so I assume you want organic visitors. But celebrity quizzes? Is there any search volume for that? I can't imagine people searching "My compatibility with Beyoncé quiz". What keyword are you trying to rank?
I don't know the field but with a quiz website, I would figure you need to draw in visitors some other ways and then funnel them to the quizzes. What other ways? Lots of ways exist, you just need to pick a path.

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Bruce
So, firstly, you allude to the fact that you more or less committed an SEO cardinal sin which was deleting blog posts that were driving organic traffic. It appears you did so because you thought the content wasn't the best. Your sentiments toward content quality are the right ones to have, but you should have evolved the content and enriched it for better results, opposed to deleting it. I would recommend reinstating your previous assets, do more in-depth keyword research and add additional headings to the content to capture more traffic. There are a couple tricks you can use. One I would suggest is looking at the queries report in the search console to see some of the terms you are already ranking for, but haven't written content about. Add relevant content that corresponds to that query, and 9/10 times your rankings will go up for that query, and you'll increase traffic. When you do it a bunch of times, it's a really powerful way of driving more traffic.
For the long-term strategy, I would recommend scaling out related, but low-competition content. This type of content inherently has lower conversions, but the amount of traffic you'll drive makes that a moot point. From those pages, you'll want to use solution-based anchor text to drive people to your money pages. How you write your Call-To-Action (CTA)s really matters, avoid sales-oriented text. Most clicks will come from anchor text users read and perceive as a solution to their problem or related to what they are reading. I'm not sure if this is transferable to what you are trying to do, but it's a powerful funnel that works and you may want to consider it.
When you're doing your research, pay hommage to competition metrics as well, not just search volume metrics. Competition metrics give you an insight into how much resources and time will be needed to rank something, if it can even be ranked at all. In many cases, I see SEO professionals make the mistake of targeting competitive terms, and then the end result is a website that ranks on page 3 for a bunch of high-volume queries which is of course not a great end result.
The other thing you may want to consider is getting away from the idea that things like an SEO health score mean anything. It makes you focus on the wrong things and have the wrong expectations. Just keep that in mind as you continue learning SEO.
Hope this helps!
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Morgan
I would suggest focusing on keyword research and content optimization. Most of the keywords you're targeting will have a relatively low competition so you should be good to rank if your content is top-notch.
Important! By content I don't only mean words, but also images, videos, and the quiz itself. If your quiz is the only content you have, make sure Google renders and indexes it correctly.
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