??

You're playing down the extent of the number of groups that would participate, the distances they would travel and the cultural significance these annual festivals had.

You understand that bronze existed before the bronze age? Because in order to successfully complete a sufficient bronze tool you do not need an entire metal works or trade caravans. Hunter gatherer groups absolutely had the time, resources and knowledge to locally produce metal tools as they needed them.

You're falling into the trap of classifying human behaviours under specific periods, bronze wasn't discovered in one place, where the bronze age began, but in many places simultaneously and over time became more significant within human society. Furthermore the existence of bronze age bronze works does not disprove the existence or practice of metal working in an earlier period.

You can build a furnace out of river mud, light it with fuel, and now all you need is the metal, which you probably would have sourced before lighting the fire. The reason bronze was valuable was because it was more ideal than copper, which is primarily the most accessible ore for hunter gatherers, since similarly to gold it can sort of be "found" in the environment. Gathering a specific resource for alloying would be more difficult without centralised population centers or long distance trading, but not impossible as some people would have lived in regions where both resources were accessible, such as Cornwall for example.

Moving away from the idea that human civilisation started when we stopped to build cities is more reflective of the archaeological evidence we have

Hunter gather societies generally held regular seasonal meetings where multiple groups would converge on a single ritual site, where knowledge, tools, resources and culture could be shared and bartered.

You do not need established cities or caravans

This is not consistent with modern insight into hunter gather societies, they were generally speaking more compassionate than we are today, if you want to measure compassion based off of a groups willingness to spend resources on social care.

Hunter gather societies, especially neanderthals, spent a much larger portion of their limited resources caring for their sick and disabled group member than we do today

I've noticed that a lot of cultures have myths around the sun and moon. Specific examples including Inuit and Egyptian folklore refers to one chasing the other. I've wondered if references to celestial bodies might actually have been describing supernova.

Personally while I doubt I would have understood what the sun or moon actually were, given I was alive during an earlier period, I can't imagine the sun or the moon would inspire much intrigue or mysticism. They've been around for an incredibly long time and early humans would have been quite used to being unable to accurately or definitively explain their environment, but imagine if one day a star brighter than the moon appeared in the sky, clearly visible during the day and slowly faded over several months.

I could imagine that experience being passed down through oral tradition, with successive generations not experiencing similar events for hundreds or thousands of years due to the rarity of said events. Successive generations may have interpreted these stories as describing the sun and moon as a result, possibly even modifying them intentionally to better narrate their environment.

Related to your point about the devastation a relatively mild flood of today's standards could have had on our ancestors and how different cultures could generate similar flood mythos as a result, I think the same could have occurred in religions or folklore from attempts to describe a variety of different events.

It would make sense that if two distinct groups experienced a volcanic eruption, earthquake or tsunami even if they were separated by a large amount of time or space, could describe these events in similar ways. Also reminiscent of folklore similarities between supernatural entities, I believe many cultures describe a demon/creature/entity that would sneak into your home as you slept to drain your strength/power/life often alongside a feeling of being crushed or held down. Personally I've always thought this could be a way of describing sleep paralysis.