Run the Lenovo hardware diagnostics.
There should be both a BIOS and bootable version.
They may have different versions and different test performance.
https://support.lenovo.com/us/en/solutions/bootableusb
https://support.lenovo.com/us/en/solutions/ht104469-flex-15-touch-screen-does-not-work-after-windows-10-upgrade
https://support.lenovo.com/us/en/solutions/ht506581-lenovo-diagnostic-solutions-downloads
https://support.lenovo.com/us/en/solutions/ht074644-run-embedded-unified-extensible-firmware-interface-uefi-diagIdeaPad%20FLEX%205-1570ostics-first
Open device manager > click view > click show hidden devices > manually expand all rows > look for any row displaying a yellow triangle with black exclamation mark or unknown device > post images or share links into this thread
If the hardware passes then reinstall the applicable driver from the Lenovo website..
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