What's hidden from most users is the configuration of the 8 cores in the SD778G (A52s) vs the new Exynos 1280. The marketing material cleverly hides it all behind "octa-core" processors.
SD778G
6nm process
1x 2.4 GHz – Kryo 670 Prime (Cortex-A78)
3x 2.2 GHz – Kryo 670 Gold (Cortex-A78)
4x 1.9 GHz – Kryo 670 Silver (Cortex-A55)
Exynos 1280
5nm process
2x 2.4 GHz – Cortex-A78
6x 2 GHz – Cortex-A55
While in theory the new Exynos 1280 should run cooler with longer battery life because of the better process (it's no mean feat to reduce it by 20%, really), the core configuration means that the A778G will outperform the Exynos 1280. The question for most would be, is that performance penalty important? For many users looking at a midrange, probably not so. For users who want that extra bit of performance from the chips (because of gaming, or even simply because you just want your phone to feel more flagship grade responsive), then yes it matters.
But from Samsung's POV, it could be to "correct" product placement "errors" in 2021. The A52s was a surprising performance king that really pushed other vendors to go all out with 8-series chips to compete. You can consider it a "spoil market" phone when you compare it with all the other midrangers within the same price bracket. Moreover, promising 3+1 years of software updates really makes it incredible value compared to alternatives in the same price range. For example, looking at the most popular alternatives, the Poco F3 and X3 (Pro, non Pro, other configurations) they were forced to play the game either with using more expensive processors (F3) or crazy high battery (X3) and the resultant problems that involve compromises to get to the same price point. I've tried 2 F3s that friends had (and have since sold) and they both have issues (heating, screen brightness randomly dimming, proximity sensor, MIUI clunkiness that was not responsive for a SD888), not unlike the infamous touchscreen issues of the Poco F1. Sad, cos I like the feel of the F3 in hand more than the A52s. The X3 was just too chunky to hold in one hand for long, so it's not really a phone I would choose. But looking at the way the market is going, it seems that >200g phones are becoming more common these days.
Hence, to be fair to Samsung with the A53, we can simply "not everyday's Sunday". We had a really good run with the A52s, but who knows what the A53s could be? Samsung had the competitive advantage, conceded/lost it this year, and may soon be forced to resume it because it's now at the level of a competitive necessity. If Xiaomi, Oppo, and other brands decide to build more powerful phones this year to combat the "A52s syndrome", then it's a buyer's market.
And objectively, the A52s is not perfect. The 1x1 antennae means that wifi traffic is noticeably slower than other phones, and it could be an issue for some.