My Buick encore has the engine cutoff when you stop will it hurt the trans to bump it in neutral before coming to a complete stop

It won't necessarily hurt it, but that'* not a use case they likely considered for everyday use.

Doing this means you'll be putting it into gear over and over as well.

I am curious: Why do you want to do this?

to stop it from cutting off

I wouldn't do that as a every time you come to a stop practice. I guess the transmission would be fine as long as you wait until it goes into gear every single time you shift from N to D. A handfull of times of getting on the gas before it engages and you'll eat a transmission. The shifter might wear out contacts etc. If you did want to use the shifter to solve this issue, I would suggest you shift to M just as you're coming to a stop, then remember to shift back to D right after you let your foot off the brake. There is less risk here as the transmission is never out of gear for this process. You have a chance of revving for no reason if you forget to shift back to D, but the PCM won't let it over-rev according to the owner'* manual.

If you're going to have the car a while, maybe look into an auto-stop/start disabler like this one:
Amazon says this fits your car, but it doesn't list your model in the description. More research is probably a good idea.

It plugs into the hood-closed sensor wire and then the engine doesn't automatically stop/start any more.

It'* too bad this car doesn't have a button to disable it like most cars.

The Start/Stop will not hurt the trans. The trans has an aux pump and accumulator to maintain line psi.