mine is also M40 recently updated I haven't faced any delays actually after updated the Phone is running smoothlym And coming to the issue, facelock is bit slow than expected, fingerprint is normal their is no delay while unlocking, pin and password will be working.
well you can turn off animations for app opening and turn off screen transition effect on lock screen ,it may help a bit . Also it may be a problem with storage with low space just check out for it . Apart from that it is from Samsung's behalf if phone is still lagging they will fix it .
Also try Restarting or may be if you like then Formatting will help . Thank you
Please follow the below mentioned steps to resolve the issue:
> Free some internal memory (If occupied more than 80%) (Settings > Device Care>Storage)
> Kindly remove the memory card from the device and then check the issue > Due to ''3rd Party'' (Not provided by Samsung) Accessories, (Like ''Charger, USB Cable'' etc.) device might also hang. So kindly avoid the usage of these 3rd party accessories. > Disable power saving mode if turned on. (Settings >Device Care >Battery> Power Mode)
For further assistance, register your concern in Samsung members app (click on “+“icon>send feedback>Error report/ Ask Questions).
