Should be all you have to do.
I was able to free mine up every year, never changed it out.
Yours will probably be good if you can remove the old one and clean it.
Diaphragm usually doesn't go bad they just get stuck.
When you free it up by cleaning polishing etc. so it fits and moves free it should work with vacuum.
Or you can swap it out for a replacement, save the stocker I believe the replacements aren't identical in looks, might be worth something in another 10 years.
EGR valve itself, not the solenoid.
If you have hose problems, or vaccum isn't getting to the valve, that would be another problem, they work at part throttle not at idle or WOT the pulsing of the EGR solenoid which causes various amounts of vaccum to open the valve while driving.
Usually it's the EGR valve that gets stuck though that is the only problem, I'd pull it out and clean it up and wire brush all the carbon off it, if it moves freely with your fingers behind it on the car and stalls it out a bit at idle I'd skip the replacement but make sure it works with the emissions chip too.