June 13 Airport strike

While this is of little value at the moment, it's worth noting that many proposed strike
actions end up not happening as things get resolved or court proceedings bar the actions
from actually occurring.

Of somewhat more value is the fact that certain intervals of times (rush hours, from what
I gather) are legally barred from having strikes affect them (I believe this is Italian law,
not EU). So if your flight is scheduled to arrive during one of those intervals, the airport cannot
be shut down. This may be what "guaranteed bands" is referring to.

At this point, it doesn't seem likely your airline will proactively reschedule your flight at
no cost to you, so you would be on the hook for any fare increases and change fees.

I would definitely research the strike law for Italy and ask your airline what your options
might be.

I'm no expert but I can share whtat I learned from dodging a half dozen strikes in Italy last fall.
First, I can see that the statement you found online was generated by AI based on general information about strikes and does not appear to be specific to June 13 or the unions or airports in the June 13 strike announcements. This does not mean the statement is false; just that it is probably too generic to make plans around.
Second, of the 4 airline related strikes announced for June 13, it looks like one is just for Venice, one is for Milan airports, one is national but not starting until 1pm and ending at 5 pm, and the remaining one is "staff of handling companies."
There is a possibility that if you are not checking bags or if it is only freight handling on strike, you might not be affected -- but you would need more information for a more informed guess.
The guaranteed time bands usually refer to certain rush hour trains running; I'm not sure how that would apply to handlers and other airport sector workers.

I found that more information becomes available in the 5 days before the announced strike date, which I know is tough for planning. I also found the tourist information center in Bologna very helpful when I was there. Perhaps emailing tourist information in Rome might help if they can clarify anything. I also suggest asking your hotel, checking local news reports closer to the date, and monitoring discussion on this forum. As another poster indicated, the strikes announced might not happen, but they also could expand to more airports or hours.