what are some signals or indicators you’d be looking at to tell whether the downturn might have bottomed?

Generally, The current price of S&P500 going above the 43 week SMA.

Note that I don't look for "the bottom". You don't need to catch the bottom to win, you just need to catch it when it is going up.

In this specific circumstance, when the situation in IRAQ is over.
And possibly when the Strait of Hormuz is open and kept open by non-US countries.
Non-US because they need it and we don't.

People have been saying that the market is overvalued for the last several years. That the market is way overdue for a correction. Anything would have triggered this correction, Iraq was just the one that happened.
I suspect that when the dust settles we'll pop back up. The US is going to come out the other side as the big winner. It will finally be widely recognized that big parts of what is called the First World are more accurately Second World.

It's hard to keep one's political positions out of one's investing. Try to keep them separate.

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I get this guy's daily email and often listen to the part of his podcast that is free. The recent one was complete for even free people. IMHO it's pretty good.

The Four Most Expensive Words Are Back
Substack: The Four Most Expensive Words Are Back

Jump to 1:04.
I ignore when he talks about technicals and support & resistance; I don't trade that way. It's the general overview that I listen to. In this one, that comes in about 21:30 & 23:00.