I think there's something to be said for effort to outcome ratios being the limiting factor.
This is why making something you genuinely enjoy can be the best approach. Because the reward you get is the satisfaction of having done it and the money you make plays a much smaller role.
Some of the most successful people I know had the initial reaction of "oh this is getting too much attention I should stop" when their things initially became popular before leaning into the interest and making businesses out of them.
There's a reason common start up advice is "solve a problem that you have."
I've tried a few things that I genuinely enjoyed and I wish I haven't, they were also problems I personally had.
Now I think the best question to ask before building anything online is: "can I sell this to people?" If the answer is no or maybe, then consider it a hobby.
Unfortunately sales is not solved by building things I love.
An alternative though is to jump on a hype train and pray that the momentum will pick you up.