Does it cease working even when the phone is fully unlocked? Generally the flashlight tap only works with an active screen (unlocking not necesary). Sounds like an annoying little bug though.I have enabled that Tap Feature where I can turn on the flashlight by tapping twice on the back of the phone. SometimesIt just ceases to function and I have to restart my phone in order for it to work again.
If iam not mistaken mid tier Samsung phones get at least one major update,not sure about the lower end phones,high end phones without a question will get a minimum 3 years warranty in some cases maybe more,security updates on anything beyond flagships are rather random and may even be delivered once in 3 or 4 months time.I'm not denying the excellent support that Samsung is providing for their phones, but they are making 'guarantees' only for the high-range mobiles.
Their low and mid-range phones are not guaranteed software upgrade support, but may get upgrades if feasible.
Please see below post where they are making the OS upgrade guarantees only for the high-range mobiles. None of the mid-range or low-range phones are in the list.
Samsung Sets the New Standard With Four Generations of OS Upgrades To Ensure the Most Up-to-Date and More Secure Galaxy ExperienceSelect Galaxy users will now enjoy the latest mobile experience for longer with four generations of One UI and Android OS upgradesnews.samsung.com