Well I also have some friends who are the same as your friends where they have a habit of doing free spins first before buying free spins, I don't know whether it's a research ritual or not, but some of them do believe that by doing so when the manual spin goes well enough then they believe that by buying free spins they will get a big win.
As you said that some succeed and some don't, but from what I see more of them fail, meaning usually out of 5 trials for example they only manage to get one or two wins and the rest lose and if calculated usually the amount cannot cover the amount of loss they previously experienced in the trial stage, and other things even though for example they managed to get a big win but it is really very difficult for them to ignore greed, like the scenario you conveyed, and because of this why bringing the intention to produce is really not recommended because in the end your expectations and hopes will continue to increase so that it will lead you to lose again.
It's ridiculous to say a ritual with something that is done specifically in gambling, some people must have their own way according to what they believe in themselves, the goal is to get a big win in the bets they make. Maybe it's more appropriate to say it as a strategy or trick because if it's called a ritual, it's very ridiculous in my opinion. Sometimes someone who spams buying free spins can succeed in getting a profitable win, but I think the amount of winnings obtained is still relatively small with the losses obtained.
I agree that spamming buying free spins is more likely to fail in getting a win, because after all the bookies have arranged everything smoothly so that they can still excel in terms of profit, even though players buy free spins in very large numbers, it does not guarantee that they can win for sure. Not to mention if the goal is to seek profit, by buying free spins and being able to produce that win, it is possible that they will become greedy, which of course this greed tends to only lead them deeper.