Since the launch of the very first foldable phone, durability has been a major concern for would-be buyers. However, Samsung has been refining the design for three generations and has made the Galaxy Z Fold3 and Z Flip3 significantly more durable than their predecessors. If you want a summary of what was done, this short video from Samsung summarizes all the upgrades. The biggest upgrade is that the third-generation Z phones are the first foldables to have water resistance with an IPX8 rating. Drop resistance has been improved as in this generation both models use Gorilla Glass Victus...
Source: https://www.gsmarena.com/samsung_releases_video_that_shows_off_the_durability_upgrades_for_the_galaxy_z_fold3_and_z_flip3-news-52281.php