Because of the dubious legality of your niche, I would suggest that you monetize your site based on some sort of e-commerce monetization strategy.
There are lots of Shopify sellers that would love to crack a deal with you.
Maybe you could get 15% of every sale.
What's important right now is for you to come up with an accurate demographic snapshot of the people visiting your download website.
I'm assuming that your 400k monthly traffic continues to grow.
This is definitely a good place to start.
Advertisers would love to convert a slice of that traffic pie.
But for you to get them excited enough to put a deal together with you, you need to come up with a way to demographically profile your traffic.
For instance, if most of your traffic comes from the United States and is made up of people that are within certain demographic groups, you might be able to get a good deal going for discounted e-commerce or merchandise products, and this can lead to some serious money.
At the end of the day, I would suggest that you try to collect emails.
After all, if something happens to your website, you still have an asset because you can still keep sending updates through your email list.
And the more updates you send, the higher the chance that you can convert some of your list members into buyers.
