To make a good performance you need to play at least in the Silver league.
The yield varies a lot because it depends on luck so there is no way to calculate the ROI correctly.
But even with no luck, you should calm down about 10% to 20% a month on average.
The ideal in my opinion is to play at least in the Golden League because there the earnings are much more substantial compared to Bronze and Silver.
As for the investment, it also depends on whether you just want to be able to play in this league, or if you want to be competitive at a high level within this league.
It also depends on whether you intend to buy or rent the cards.
Buying the cards the investment has to be much higher in the hundreds of dollars while renting it is much cheaper since you can rent entire collections for a few cents on each card.
How much you can win depends on luck when opening chests, and your results, if you win a lot of battles you win more if you win tournaments too.
If you do well in tournaments you can make 100,000+ DEC in one day, if you do poorly, I won't win anything.
When opening a chest you can receive a +500 dollar valuable card, or just 1 potion almost worthless, so better not try to quantify, but start playing, the longer you play, the more chance of receiving something good.
I get confused, and I don't know how to respond in the best way.
In my opinion, Splinterlands is much more interesting and fun, but Axie has this advantage, it is much easier to quantify Return on Investment and the reason is the Adventure Mode.
The Arena, ie the Player versus Player Mode is also variable, it depends on whether your team is good and your ability to win more battles, however, the Adventure Mode will give you a sense of the least you can do in terms of profit, compared to how much money you need to invest.
So of course, investing more will give you an advantage in PvP, and the fluctuation of the token value you earn also varies, but even so, it will be possible to get a much more accurate notion and you can tell what the person will be able to do for sure in PvE currently, this is in Adventure Mode.
That's why I believe Splinterlands should make it a top priority to launch an Adventure Mode, in which the player fights certain computer-controlled enemies, passes certain stages, battles bosses, evolves, etc.
In my opinion, this would make a hugely larger amount of players come in and start playing today.
So I could give a much simpler answer:
You invest X and win Y, with some variation, but not those vague and complex answers that make a person give up investing in a few minutes.
What's up? What do you think of the idea? Will we have enough SPS to pass Adventure Mode?