A topic as old as 5E, if not older. And every time I personnally struggle to see any kind of problem.
I mean, sure, if you're there for a pure tactical-puzzle solving wargame, you'd have to to follow the 6-8 encounters advice and the story might feel tedious or disjointed, but... you're not here for the story, but for the tactical-puzzle solving. So, it's all good. You can play like that, as written.
And if you don't particularly care about this and are here mainly for the story and the occasional thrill of combat and adventure, as many casual players are (and I mean casual here as in "casual players of DnD specifically", they can nevertheless be hardcore rpg players), well, who cares about the 6-8 encounters? One really tough battle once in a while will be enough, and it's trivially easy to imagine one on the DM side, especially in 5E24 whose encounter building rules seem exactly built for that; centered around a single encounter, rather than the adventuring day.
Sure, you'll have some swingy results, but isn't it best for the story, if that's what you're after? Given that 0 HP is almost never a synonym of ultimate death, given that you can always surrendrer or flee or whatever, I fail to see how this kind of outputs, the unexpected openings of surprising story paths, would be a problem — provided once again that the wargaming aspect is secondary, that you're not here, or not here exclusively, for a balanced challenge.
I'll add that is also one of the best ways, IMO, to play engaging battles:
— engaging because they will be quick, around the three rounds mark and the 20-30 minutes of play which are close to the optimum time for casual players,
— engaging because they don't have to be played to the last hit point, hence avoiding the final unintersting slog when the outcome is already known,
—engaging because they won't ever be filler battles. All will have a narrative purpose, a narrative goal and several different interesting outcomes.