It's a gamble, I surely wouldn't use a KitKat phone for internet browsing, it is probably no different from using an ancient version of IE from 20 years ago, it

It's a gamble, I surely wouldn't use a KitKat phone for internet browsing, it is probably no different from using an ancient version of IE from 20 years ago, it is just a matter of time before something bad happens. The biggest problem is, most OEMs nowadays lock bootloaders and make it a lot tougher to use custom ROMs for longer support, non malicious pre-installed applications, and removing Google services - almost non-existent FOSS support from Qualcomm devices doesn't help either. I only buy for myself and suggest to others devices that are more likely to get community driven support, that for example bars some manufacturers with ridiculous lock-ins.