I don't know why people are villainising the concept of a "beach episode".
We fought one lord ravager with the fate of the entire universe at stake in 3.8. Then we came to Himeko's homeworld seeking a "vacation" in the words of March 7th and found what? A gag boss in 4.0, a Pompom Mechatron that La Mancha needs to go all out on in 4.1, then a Shuhu abundance plot that very nearly got a Lux arrow sent to the planet and... wait! Another lord ravager who we'll showdown against next patch.
After all that people seriously wanted Robin and Aventurine to get lore powerups to take down another anatagonist in the first patch of a Holiday Resort planet under the Preservation's protection? The beach episode is a necessary reprieve to relax the plot and get us away from the threat of cheap Marvel-adjacent end-of-the-world level stakes.
And for the lore players out there, there is a suitable lore explanation if you actually bother to look. Remember, Robin is a galactic idol who wants to investigate the IPC's true intentions behind the Anti-Destruction Alliance on behalf of the Family. She can't exactly just walk in and start snooping around as a literal celebrity can she? She signed a contraact with the IPC to put on a summer show in Astropolis, which gives the IPC the profit it always seeks and her a non-suspicious way of entering IPC headquarters.