You have to make sure you have the right to use it for commercial stock, which is the main reason you are paying.

Midjourney is the most popular tool with the best results. However, unless you are on their more expensive monthly plans everything you "create" is public and can be downloaded and used by anybody else on their platform.

Then there is the whole problem that most ai companies never legally licensed the ai training material, they just stole everything from the internet and fed it into their pixel mixing machine.

If you want to be legally safe, the the Adobe firefly generator is probably your best option.

The quality created is not as good midjourney, but you don't have the legal problems and all your "prompting" is private.

There are many social media groups where people openly share prompts, results and ideas.

You will also have to learn how to upsize the generated files in a way without artifacts. The post processing is an art on it's own.

My suggestion: just find an ai app or page where you can just do it for fun, join a few social media groups and just create stuff for yourself as a hobby.

ai apps are really cheap, just a few euros for a full version.

when you feel comfortable with that, then perhaps try firefly because that can be used legally for uploading to Adobe.

I know some people that ONLY use firefly with excellent results. For me it doesn't work that well.

Every ai engine is different and it takes time to learn to get what you want.

The whole legal part if we have any kind of copyright over the work we create is also in total legal limbo and will probably take years to be resolved.

But you don't need ai to make money in the stock world. Many producers still make a full time living without touching ai.

In fact, it might be a lot more important if you spend the next 18 months trying very hard to find "your" customers and client niche.

Once you have that settled you can expand what you offer for the genre with ai.

Just my 2 cents.

"I've seen macro photography it's in trend. Will need to try that as well."

It needs to be perfectly and professionally lit and shot, often using stacking techniques. You are competing with the entire planet and macro photography can be doe from home ...even more competition.

Maybe take a few specialised classed if somebody can teach you. Saves months of time. Or join a macro photo club.

For stock doing macro of technology close ups, industrial style backgrounds etc..might make more money than another flower and insect portfolio.

Extreme high quality is the most important. Only upload your very, very best to make a great impression.

Have fun!