How can I display space between pages in Pages on iMac?

There is no design or setting feature in Pages to display pages with any inter-pagination space. Microsoft Word does this by default. If this pagination spacing effect is important to you, then use the correct word processing application.

The current version of Pages is v14.4. Owing to the operating system interface changes in the forthcoming macOS Tahoe, you should stay current with Pages on Sequoia as there is a likelyhood that a new version of Pages reflecting the user interface changes in Tahoe, will not be installable on Sequoia this Fall.

You can send direct feedback with a feature request to the Pages product team from the Pages application menu. That is the only way they will see your preference for page separation. No Apple employees participate in these public communities.

It was never Apple's design intention to give Pages a decidedly MS Word appearance through out the last 20 years of its existence and there will be headwinds to any sort of change to the contrary.

It took Apple eight years to re-implement non-contiguous text selection in Pages. Silly is as silly does, so we cannot assume anything about internal product team design decisions or their reaction to requested features.

Right now, I would expect the Pages product team has their hands full applying the forthcoming macOS Tahoe user interface updates to the very likely Tahoe-exclusive release of a future Pages version.