I think OP is trying to raise his bars to accommodate an aging back. If (1) you're keeping the same bike, and (2) the steerer was cut so there was only room for a 5 mm spacer, then adding spacers isn't an option.


With modern 4-bolt faceplate stems, flipping the stem is eminently reasonable.


If there's not too much difference in bar height, 10 minutes in the garage/shop and you're done. You may need to recable, especially the front brake, if there's a significant change.


There will be no difference in handling for a given bar height how you get there. If some young sprout tries to give you grief over style points, well, this is a good chance to practice kiddy put-downs for when you get even older!