These two statements are in direct contradiction to each other.
Strengthening the weaker options while at the same time not weakening the stronger options is power creep, all day long: the average has become more powerful.
There is no power creep.
When a player, I evaluate the character options for each feature. I rate them from worst to best: subpar, meh, good, and excellent. (I note if any of the excellent ones are too excellent for their current level or even game breaking. Nerfs are rare but they do happen.) The subpar and meh options are nonviable and dont exist in my eyes. I hate game imbalance because it means fewer choices in a game about choices. Only the good and excellent choices exist in my eyes.
There is no power creep because D&D 2024 filled every decision point with good and excellent choices. Features that didnt even exist because they were subpar, now enter existence with appealing possibilities. Sometimes entire classes, species, and feats, manifest as if out of nowhere because they now offer good and excellent choices.
Barbarians are effectively neutered by changes to their class mechanics and enemy design. Druids' unique features are nerfed in favour of imitating Cleric features. Rangers are derailed into "Hunter's Mark, the class". Monks can't do anything meaningful except punch people and aren't even any better at dealing damage than more versatile classes.
The Lucky feat is nerfed, but a new origin feat confers the exact same benefit to multiple characters, multiple times a day. Healer is nerfed, while Magic Initiate is made significantly stronger. Crafter and Savage Attacker are completely useless in comparison to most options.
Imbalance is baked into every aspect of 2024 5e.
I say there is no power creep. There are still a few options that are concerning. But these are incidental problems, not system problems.
I agree the Lucky feat is too excellent, compared to the rest of the options. (But not broken.) Luck-Fate-Spacetime is an important archetype and needs to be there at the origin level. Yet it merits recalibration. I would split it into Lucky for ones own alliance, and Unlucky against hostiles. These two distinctions are also archetypally significant.
Spellcasting rules are changed to benefit some subclasses and builds over others.
The functionality of the game engine, especially for higher levels, needs every spell in a slot to be about equally appealing. Spell slots need a smooth continuum, that is also used to measure higher level nonspell options.
It is ok if a class feature improves a particular spell, but the spell itself needs to equal the other spells of the slot. I would rather Eldritch Blast be a normal cantrip, with less damage that a Warlock feature can improve.
I know some players want each class to have "niche spells". But I prefer such specializations to be class mechanics, not imbalanced spells.
Numerous options that weren't even considered that strong were made even worse for no reason. Even with a new mechanic, Weapon Mastery, the designers were fully aware that certain masteries were far better than others and would be the primary picks of the majority of players
Because of the variables in play, I expect designers want Weapon Mastery out in the wild with all of the exploitable combos, before finetuning the Masteries for balance.
Anyway, I love the game engine of D&D 2024. I like how it arranges backgrounds, feats, species, and classes. It is a great consolidation of 2014. 2014 did an excellent job of nerfing the broken options of earlier editions. 2024 does an excellent job of improving the subpar options.
D&D is an evolving game. It is valuable when DMs and players voice their personal preferences, while accepting a kind of democracy whose majority determines the eventual outcomes. Part of the job of the designers is figuring out how to implement conflictive preferences.