If the value of Bitcoin plummets, then the profitability of mining drops, then miners drop out, and the remaining miners become more profitable. The difficulty adjusts and the issuance rate remains stable.

If the value soars, the profitability goes up and new entrants enter the mining game. Then the difficulty adjusts and the issuances rate remains stable.

I don’t understand your second scenario at all. The price falling makes transactions prohibitively expensive? Do you mean the price of bitcoin falls to where no one can mine it profitably? That era already came and went and it did not lead to collapse of the value, quite the opposite.

Also, your opinion that bitcoins are “worthless” is just one opinion, there are 8 billion others that affect whether bitcoins have worth or not, and currently one is worth ~$48k.

I think you might be misunderstanding the difference between miners producing blocks and users submitting transactions, as well as block reward versus transaction fees. At least you’re mixing up the terminology and your meaning is unclear.