Are shop items locked behind real money?

What money changes is speed and quantity, not what you can own. Paid bundles and battle passes hand out higher-tier capture pods in larger amounts, but none of them contains a gameplay item that is missing from normal play.

The shop packs themselves carry cosmetics, capture items and progression materials such as Sparkling Crystals and Sparkling Cubes. Every one of those can be earned by playing. If you are free to play, you are on the same road as a paying player, only slower.

The sharpest shortcut is stamina. Real money buys extra stamina, which lets a paying player go past the daily and weekly energy limits that cap everyone else. That is a pace advantage rather than a locked item, but it is the place where spending most directly turns into more progress per day.

Where the battle pass pulls ahead

The premium Companion Handbook is the closest thing to a paid head start. Buying the Advanced or Collector's edition instantly grants 10 levels of progress, and the Advanced Companion Handbook awards an exclusive Prismana egg at level 10, giving early access to that season's featured Prismana Aniimo. The specific egg changes between seasons and versions. Early access is the point: you get the featured Prismana sooner, not a creature that free players are shut out of.

Not settled: The Prismana egg from the Advanced Companion Handbook is the one reward sold as early access rather than as a plain shortcut, and how long free players wait for each season's featured Prismana depends on the season.