You can protect yourself, but many won't be aware of the situation until it's too late, and institutionally managed funds won't be able to change their rules in time to avoid holding these as part of the index funds they hold.

Many individuals can, but good luck reaching out and convincing the entire country that they should look into making changes to their retirement fund allocations without sounding like a kook.

There's maybe, at best, 1% of the country even aware that this might be a problem.

What should we be looking for?

In your 401k portal/website there's usually a setting like "I plan to retire on year X". When you set that, or something similar, there's typically a managed fund that gradually decreases risk as you approach that year. When you have lots of time before retirement you can ride the ups and downs but as you get closer the less time you have to recover from a downturn so the more conservative you want your investments.

If you're really worried and want to be conservative tell the portal you want to retire in 2030. That will allocate your investments to something conservative and you'll be more protected from a downturn. On the other hand, you'll also be equally protected from an upswing.

/not a financial advisor

I’m not sure I could. Even starting to research how to prevent being affected by these changes shows that there’s layers upon layers of systems that are being manipulated, and there are costs charged for moving the capital in my retirement account to other accounts.

Saying you as in any random person can protect themself from a group of dedicated experts who also have access to levers the common person can’t pull, is kind of not believable on its face.

I actually cannot adjust the index funds offered.

Does your plan support BrokerageLink?