Its not payment structure thats the issue for Barca, that was back when Barto took temporary loans with the La Liga wage cap was still much higher for Barca and no issue with that one (their revenue was ridiculous but their
long term costs even more ridiculous)..
short of cash, now its the other way around, they have been so conditioned with the massive lowering of the La Liga wage cap the last few years, from like 800m to 500m or so, its the amortisation (contract length, salary), and+ transfer sum thats the issue (LL ffp), nothing to do with payment structure.
This is why La Liga is last on this list. They must make back the 3 impacted Covid years unproportionally.
I still doubt they will buy him though.
Serie A is in reality in much, much worse shape (financially) than la Liga for instance. Basically all top ten clubs in La Liga except for Real Madrid and Real Sociedad are having a short-
ish term issues with this, Barca of course have big, big long term issues as well though..
Noting is happening with Atleti as well.. they are at a standstill with Morata, Amrabat, Højbjerg etc etc cos they cant fit it under the cost cap until people actually financially leave. And it just becomes a waiting game for the parties.
This is why La Liga in principal will not buy from PL the last few years, except for some home comers probably, and they will sometime have to wait a year or get loaned out like Betis for Bellerin last season and Collado this.
For instance Barca probably cant afford to loan him a year on full wages+ pay a loan fee like 7m under the LL salary limit but they could more likely buy him then on a 4-5y contract+on less wages to get the annual LL FFP rate down.
And thats why there are reports of him lowering his wages temporary? for him to even get his move (Spain), unless he wants to go to Saudi.