I understand what you are saying, but for me the point is not to spend hugely on that 300m and later get into the same mess regarding not being able to pay recurrent big expenses.
We are talking about different things in the end. I'm talking more about expenses, you're talking more about FFP. In my opinion both are major issues. Not just FFP.
Let's say I make 10k a month, but during the year I owe all of that and even more, let's 150k. Now I can't really afford to buy many expensive things with my money. It's the same thing. Barca's revenue is gonna be much lower this year than the last year (no levers and no camp nou is gonna cause a steep decline), so it means those 300m are gonna be, at least most of it, used to plug the gap and continue to make due payments.
That's until the new Camp Nou kicks in. That's the plan probably. Those money that are gonna be used to cover for loss of organic revenue. Then Camp Nou kicks in, the young players are more mature by then and hopefully explode into superstars, and the organic revenue gets close to what it was pre-covid.
Of course that the club could have bought other players instead of the ones that we bought in 2022, if that's what you're aiming at. That goes without saying, but I doubt very much that Barca have money to spend right now, even ignoring the La Liga FFP situation. That's exactly why it's there in the first place. To prevent Barcelona for spending money that they don't have. They may have it now, for a brief moment because of various schemes, but they won't have it long enough to deal with long term big expenses.