Remember, it is normal for the Preloader port to appear and then disappear. The SP Flash Tool is designed to "catch" the connection the moment it appears. You should click "Download" in the tool before plugging in your phone.
Since Windows 8 and continuing through Windows 10 and 11, Microsoft has implemented a strict security feature that prevents the installation of drivers that are not digitally signed by a trusted certificate authority. The MT65xx Preloader drivers, many of which date back several years or are open-source variants, often lack these modern signatures. mt65xx preloader driver
Always use a high-quality data cable. Avoid USB 3.0 (blue) ports if possible; older MTK chipsets often prefer USB 2.0 ports . Remember, it is normal for the Preloader port
: A transient state (usually lasting only a few seconds) when the device is first plugged in while powered off. Since Windows 8 and continuing through Windows 10