Are there any instructions on bypassing Google Play and selling direct? I'm curious about signing, is it ok to upload the apk unsigned?
You could sell on your own site, but your customers would have to allow for an installation of apps from unknown sources.
Ok, that’s what I’m going to go with. There are benefits to this including getting 100% revenue and no need to split APK.
But it also has a downside you have to reach to your customers by yourself and it requires more effort for our customers to update the app.
Unless you are Fortnite its not a good idea, you will get so much less downloads (and less money) from your app in aggregate.
One possiblity is to do both Google Play and direct. On the Google Play page mention direct purchase is available via website. That way you get the best of both worlds (app discoverability plus 100% revenue). You could also discount the app 5% on your website to entice people to buy there. 95% is still way better than 70%.
Do you know if there is a way to become a trusted source so that the end users don't have to change their settings?
But why? If your game is good enough to make it through the sludge of mobile games then it won't matter if its 70% or 100% you will make a good living either way. Focus on making a good game first then worry about % of revenue after.
I do not think it is an easy way to become a trusted source of applications. If it was easy then it would be less secure. Much like SSL certificates, only companies that can prove they have secure infrastructure can become CA.
You can't get trusted without Play. (I assume we are not talking of alternative stores like Amazon, chinese stores etc.) You also have to take care of the distribution (hosting and traffic), security, updates, promotion and many other things which Google does for you if you choose Play.