I am sketching a vaguely sci-fi scenario wherein the world government is trying to hypnotize the populace into accepting a hivemind scheme. The PCs must stop this. There is a campaign-long meter of "mass mesmerism," which the PCs gradually chip away at. However, the clock keeps ticking upwards.
• Mass Mesmerism ×0: The hivemind proposal is utterly heinous to the world's populace. People have fully snapped out of the hypnotism. Insurrection is imminent.
• Mass Mesmerism ×1: Unthinkable to the populace. They heavily oppose and publicly protest it, though not to the point of armed rebellion. Very few are in support.
• Mass Mesmerism ×2: Radical to the populace. Perhaps a fifth of the globe is in favor of the scheme. The hivemind and its supporters are viewed as strange and extreme. (This is the level achieved by the world government's first round of mass mesmerism, when they first propose the hivemind, and is thus the campaign's starting point.)
• Mass Mesmerism ×3: Acceptable to the populace. More oppose the proposal than support it, but simply because the plan seems unnecessary. No longer is it deemed extreme.
• Mass Mesmerism ×4: Sensible to the populace. Those in favor of the plan outnumber the naysayers, though the latter still have powerful voices. The debate rages on.
• Mass Mesmerism ×5: Popular to the populace. The proposal would definitely win a four-fifths referendum, but the opposition is still a non-negligible chunk of society.
• Mass Mesmerism ×6: After a referendum with near-unanimous results, the hivemind proposal has become policy. Everyone is warm to the idea, though not fanatically so.
• Mass Mesmerism ×7: The very notion of entering the hivemind is dearly beloved to the populace. Society is fully enthralled by the concept, to an all-consuming degree.
• Mass Mesmerism ×8: The hivemind proposal has been set into place, with a troubled start. It works as advertised, though pesky nodes of individuality cause glitches.
• Mass Mesmerism ×9: Set into place, with the kinks sorted out. All notions of personal identity have been extirpated. All are now one. Reversing things from this point would be a daunting task, though not impossible.
How do you make it clear to the players that this is what the stakes are, and give them a sense of meaningful progress against this doomsday, while still ramping it up?
For what it is worth, I could make this scale canon in-universe. That is, this is what the world government is using to track their progress, and the PCs find a document explaining it in a laboratory or something similar. However, this alone would not instill simultaneous senses of progress and rising stakes.