The '70s episode brings back HYDRA again, but that's not even close to the most significant element of the commercial.
"Need a break?" asks the male narrator, to which the "housewife" replies, "You read my mind." Given what we know about Wanda's powers, this could be a reference to how she's "inside" the minds of all the Westview residents, but it also could mean something more sinister.
The other interpretation is that someone else, an outside force, is the one doing the mind reading, and Wanda is represented by the housewife who needs to "escape to a world all your own, where your problems float away." as the narrator says. The entire world of WandaVision is clearly crafted as an escape for Wanda, who's intensely grieving, but this commercial hints that maybe Wanda's not the one in control, since "HYDRA Soak" bubble bath is responsible for this housewife's relaxation.
Instead, it's possible Wanda was tempted or tricked by another, sinister entity. The final slogan, "Find the Goddess Within" is particularly eerie, given what happens in this episode. The '70s episode features the birth of Wanda and Vision's twins, who, in the comics, are actually formed from the demon Mephisto. Given the odd "goddess" reference in this commercial, it could be suggesting that HYDRA is just the tip of the iceberg when it comes to evil entities taking advantage of Wanda.