Shafts to long?

Driver length and irons length do not correlate .... of course, it depends on the irons and how you are hitting them.

A lot of guys cut a 45.5-46 driver to 44.5-45.

Irons -- A more traditional standard 5i is 37.5-37.75 inches. The top of the grip adds .25 inches, so subtract if you are measuring to the top of the grip. Some people think a 5i standard is 38 inches. If it's more than 38, I'd be concerned.

But it also matters whether you are standard as to length of arms, height, etc., and whether you were fit for the irons you are playing.

What is the 5i length of your irons?

Mizuno tends to run 37.75 in the 5i.

To test, I would put some tennis grip tape on the lower part of your grip to build it up,  grip down .5 inches, and see how you hit them. It  will give you an idea, and/or forget the first part and get to someone who does fittings and see what they say. You do not want to cut too much, because once it's cut, it's cut.

Be careful on putting too much emphasis on your "wrist to floor" measurement. It serves as a rough starting point to suggest shaft length for initial fitting. (from GolfWorks school)

Your stance and posture are much more important in determining proper shaft length.

The issues that come up if you shorten an iron 1 inch from the butt end are:

The swingweight changes by 6 points lighter. Some people will not like the feel. You could use a lighter grip to restore the feel. The other solution is to install tip weights in the shaft.

The flex is stiffer but only slightly.

The lie of the iron will need to be adjusted, probably.

All of this can be fixed of course, a clubfitter can make the adjustments.

The easiest test is to use impact tape to see how often you hit the sweet spot.

If you are hitting the irons consistently you could play them as is.