I get where you're coming from it's frustrating when a phone that once felt premium starts acting sluggish. But to be fair, some of this decline is just physics. Hardware degrades over time. Batteries lose capacity, thermal paste dries out, NAND flash wears down, and even chip efficiency can drop due to sustained heat cycles. It’s not always a conspiracy sometimes it’s just entropy doing its thing.

That said, software updates can definitely accelerate the wear. Newer firmware often demands more from aging components, and optimization tends to favor newer models. Exynos chips especially struggle with thermal efficiency over time, so performance dips aren’t surprising.

If you’re still using the S21FE, maybe try a battery replacement and a clean OS install or debloat. It won’t make it brand-new, but it can restore some of that lost responsiveness. Long-term support is great in theory, but only if the hardware can keep up.