Yes, of course, the elevator trim controls the IAS in level flight, because for a given aircraft configuration it controls the pitch attitude and that relates to the IAS.
If you go into a spiral dive then your IAS will increase
The reason why appreciating that the trim controls the
speed is so useful is because most normal flight is done with the wings level, or nearly so.
one way to slow down without changing altitude is to pull to higher angle of attack and roll 360 degrees.
I think the space shuttle did that, and similarly with most re-entry vehicles before it, to lose speed once in the uppermost layers of the atmosphere (because once you drop below the escape velocity then re-entry is guaranteed, which is highly desirable) though obviously not rolling through 360 degrees
That's why one does S-turns on final. That is arguably a lot safer than sideslipping, which on some aircraft types might cause problems with elevator airflow.