Spanish football's different. Outside of Barça, Atletico, Real, Sevilla & this season Girona, most games in La Liga are against bottom third of the PL, to the top half of the Championship level opponents at best. This is why the elite Spanish teams can afford to put so much emphasis on Europe.
Imagine Real if they had Liverpool away, Leipsig away, then West Ham at home, & a tricky Carabao Cup tie away to Chelsea, all in the space of 12 days? That's a whole different level of football to what Real face on a regular basis, but EPL clubs face most weeks.
In this regard I'd expect elite players to perform to the highest standards in most La Liga matches, as the level of opposition is generally lower.
For years the two best players of their generation spent week after week in Spain playing against Elche, Oviedo, Levante & Tenerife etc, with the odd Sevilla, Valencia or Atletico match thrown into the mix. Is it any surprise Messi & Ronaldo were scoring 60, 70 goals per season?
I'm not saying Bellingham isn't an elite player, but has he been more effective than Rodri, KDB, Gundog, Bernardo or for that matter Phil Foden this year? No chance! And our lot have got the medals & scars to prove it.