Although Serendipity is more on the romance side and lacks the bromance that Spirealm has, both of the story bases are similar - in both shows they visit different worlds (VR games/books) with different settings, solve problems and find out about mysteries.

They have similar vibes with great plot, cool and fun MCs, both have a group of friends who learns to trust and rely on each other and tries to save the day. There is a bit of school setting, however in Tiger and Crane it is only a little part of the whole story.
Both ML is clever and strong, has a more mature and stoic best friend.
Also both female leads are great fighters and strong individuals.