I think its pretty obvious it wouldve been more difficult. Spain lacked a cutting edge but they're obviously a better side then Russia, hence them breaking passing records. Against Russia, England would play their normal style and have better players all over the pitch and dominate and probably win. Against Spain, England would sit back and have very little possession, rely on random counters and hope Spain have an off day as Spain have better individuals. Same situation with Germany. They had bad tactics and awful finishing and a bad mentality, but they'd still dominate possession, pressure England and create a lot of chances. Them finishing bottom doesnt change the fact that they had the most shots out of anyone and all the possession.
Being resilient to hold them off, smart and clinical on the break is what's needed against those. It's a completely different game playing Sweden/Russia when you play your normal game, or spain/Germany where they dominate the ball and make you change.