Peaks are defined by the space in between
People, as a general rule, are much better at comparing things than they are at measuring absolutes. That's why we don't measure pain in kilo-ouches, but instead tell the doctor that "it hurts twice as much as a stubbed toe". The same thing is true for story telling. If you want a big, epic confrontation to feel more epic, then you surround it with smaller confrontations.
Episodic TV shows naturally have this sort of pacing. After a big show-stopping season finale where The Doctor saves all of time itself, they'll go back to saving hospitals, cities, and individuals. Then the next season finale will roll around and it's time for another epic confrontation. But because of the smaller stories in between this one and the previous finale, they're no longer in direct comparison, and while it still needs to be epic it doesn't necessarily have to be more epic.
Readers like these sorts of structures. High drama is exhausting, and after a particularly tense climax it is nice to relax and enjoy something with slightly lower stakes for a while.
"Personal's not the same as important. People just think it is."
-Terry Pratchett, Lords and Ladies (and later Men at Arms)
Conflict is measured by the stakes involved. But it's measured by how much the stakes matter to the readers and characters rather than how much they matter overall. The chance to earn the forgiveness of a loved one can be just as dramatic as the fate of the entire world.
An excellent example of this principal can be found in the Dresden Files (although I'll have to be slightly oblique about it to avoid spoilers). While I haven't taken a poll, I think that it's safe to say that as of this writing the most climactic book of the series is book twelve, Changes. But if you actually measure the potential death toll of villainous victories, several of the other books (particularly Dead Beat and Cold Days, both of which threaten the immediate destruction of most of Chicago and a great deal of bad followup afterwards) actually have higher stakes. But Changes feels the most dramatic because in that book the stakes are intensely personal.
By making the stakes more personal you can increase the tension the readers feel without making the stakes feel ridiculously over-the-top.
Effects can matter as much as stakes
The other reason Changes feels more dramatic than the other books is that Changes lives up to its name and significantly shakes up the status quo. In most of the books, after the antagonist is defeated, things mostly go back to normal. Harry might have a new injury, or a new ally, or a new tool (or all three), but mostly things stay the same. That's not the case with Changes, and that makes the conflict feel more serious than the surrounding books.
The more the conflict changes the protagonists, the more epic it will feel regardless of stakes.
Change the type of threat, and play to your hero's weaknesses
Part of the problem is that there is a natural power creep in long running stories. Once your hero levels up their vampire-melting death ray so that they can defeat Dracula, then it becomes difficult to reach the same level of threat from any vampire that's equal to or weaker than Dracula ever again. So you get a more powerful vampire, but once they've beaten that one they need an even more powerful one...
Of course, you could de-power your hero, but that gets old pretty fast, and readers like powerful heroes.
But if, instead of throwing another vampire at your hero you instead throw a werewolf - then suddenly their vampire-melting ray is useless! By changing up the types of threats your protagonists face, you can moderate the power level of those threats while still keeping things interesting.
By using threats that are outside of your hero's area of expertise, you can stymie them with threats that another protagonist might find significantly less threatening than what they previously faced. A corrupt politician might seem like nothing compared to a dragon the size of a house, but the Hulk will have a much harder time dealing with the politician.
As a bonus, pushing a hero outside their comfort zone is an excellent way to provoke change and character growth.
All told, variation is the key to success. If the hero faces the same thing every time, then by necessity each threat must be bigger than the previous one, because that's the only way to compare them. But by changing the stakes, and the possible solutions, and the effects of the conflict you can make each one feel individually dramatic without having to upstage your previous conflicts.