If you have the time and the energy, reupload the photos that are rejected and you will be surprised they will be approved, of course, if you're lucky they are reviewed by another person ;)
I know people who do that and their photos get approved finally :)))
I have done that a few times when I know the rejection is unjust. It happens on videos where they're rejected for missing frames or shaky video despite being drone shots that have nothing wrong with them; I've even contacted support a few times over it and they end up fixing it for me.
I'm a little more cautious with Adobe though as I see a lot of stories of accounts getting closed. Wouldn't wanna keep submitting things that end up rejected and perhaps end up getting that ban hammer for some reason. Sold my first image on there today for a dollar though, which was nice. Shutterstock is definitely more relaxed in that regard, where they'll just tell you what's wrong and get you to resubmit if it's something you can fix.
I think I'll stick to videos for the most part anyway, they make significantly more money and I have a bit more fun shooting aerial stuff.
Everything in Stock is so subjective, yes.
shutterstock was one of my first agencies, I started around year 2013 but they got extremely greedy and instead of cutting their expenses they started to rob contributors. The best evidence for this is cutting the minimum payment per photo from $0.25 to $0.10. In a world with inflation and increasing prices, this is just ugly. I don't upload there anymore, not I suggest a photographer does. It is just plain robbery. Some of the colleagues deleted completely their contributor accounts at SS.