I mean, is cannibalism really the worst problem here?
Humans are omnivores and if the alternative is to throw unused human parts underground or cremate them, feeding them to new humans is at least not a waste.
Yes, Firefox would also be a great alternative. Chromium itself, on which kiwi is based, is a open source webbrowser supported by large corporations. The underlying blink engine combined with the similar WebKit from safari, has a combined market share of over 70%(over 80% on desktop). This can be both a positive or a negative. For you the user, it ensures compatibility. Every website with any kind of active development, will run in your browser, as who would ignore over 70% of the market?
Though while it is open source, having one engine this big, and being mostly backed by large corporations, will possibly bring issues similar to the internet explorer days of old. A stagnating non open standardized web. This makes our support for alternatives a possible necessity to ensure a open and free web.
Firefox is a great alternative, though of course with its own quirks. Being on the smaller side, though rare, means website support isn’t always there, so that would be something you’d have to be able to deal with. I would definitely try the browser yourself and see if it fits the purpose you seek.