exchanging euros before departure to Italy

If you absolutely must have Euros in your pocket before arriving then by all means get Euros before you leave. Of course you should take a debit card (and notify your bank) so that you can withdraw cash from ATMs.

Absolutely take your debit card to withdraw cash (preferably at Bank ATMs) while in Italy. But first check with your bank that it will work over there, and notify them of your dates and which countries you will be visiting, so it doesn't send up a fraud alert.

As for buying euros before you leave, you are going to get varying responses. I prefer to have a couple hundred euros in my moneybelt before I arrive. I know I'm going to be semi zombie like by the time I land, and won't want to putz around looking for an ATM at the arrival airport. Once my initial stash starts running low, we'll find a bank ATM (during their open hours, in case there's a problem) to replenish. Others just get their Euros from the ATM when they land.

I, also, like to have some local currency when I hit the ground but I also have the luxury of having € and £ on-hand from previous travels. I don't, however, think it's necessary. What is necessary is to get thoroughly acquainted with all the money issues you'll likely encounter. A good place to start is Rick's money tips (here).

The short of it:

Debit card withdrawals are the most cost-effective means of getting local currency. But, credit card cash advances at ATMs, while convenient, often have very high fees.

Notify each card issuer of your travel itinerary. This is usually done with a phone call but some banks now allow you to do it on-line in their portal. Don't forget to include any intermediate stops if changing flights at a European hub airport (London, Paris, Amsterdam, etc.) just in case you are delayed for some reason.

ATM transactions normally have a daily withdrawal limit. Know the limit beforehand, especially if you are planning to pay for hotel rooms with cash. You can also discuss with your bank temporary daily limit increases.

If you are taking your credit card(s) request a Personal Identification Number (PIN) several weeks before you leave. You may be required to use your PIN to make purchases...

If your card gets "locked" due to suspected fraudulent activity, you may still be able to use the card by calling the issuer and having the block temporarily lifted for specific purchases (hotel bill, etc.) It's a royal pain but it can get you out of a jam.

I am mathematically challenged on my best days, so I like to have at least enough euro to get me to my hotel. I can find a Bancomat the next morning. I use leftovers from the previous trip, but I would order €100-200 to get you started.

I find bringing some euros is a good idea. I take a few hundred.

After 10+ hours of being dehydrated and hypnotized by the engine drone, my higher brain function is minimal

Somewhere from zero to a hundred EUR depending on your arrival airport and first destination.

Zero EUR if you follow Rick Steve's Cash and Currency Tips: https://www.ricksteves.com/travel-tips/money/cash-tips

Avoid (or at least minimize) cash exchange. The financial industry does a masterful job of hiding the fact that you lose money
each time you change it. On average, at a bank you lose 8 percent when
you change dollars to euros or another foreign currency.

Don’t buy foreign currency in advance. Some tourists just have to have euros or pounds in their pockets when they step off the airplane,
but smart travelers don’t bother and know better than to get lousy
stateside exchange rates. Wait until you arrive at your destination;
I’ve never been to an airport in Europe that didn’t have plenty of
ATMs.

If you are one of those who "need" or feel comfortable having local currency in pocket on landing, a minimal amount (100 EUR) or approximately the amount to pay for transportation from airport to hotel is all you need. Hotel can direct you to a nearby bank operated ATM. Then follow Rick Steves' ATM advice: https://www.ricksteves.com/travel-tips/money/cash-machine-atm-tips

I really don't see the point in getting Euros ahead of time. Are people really too tired to use the ATM at the airport upon arrival? You can pay for almost everything with a credit card nowadays, anyway.

I always bring a few hundred USD with me just in case of emergencies, to exchange in the event I can't get cash from an ATM and can't use a credit card or something. But I've never needed it.

We usually take a hundred or two Euros with us so we can have ready cash to use when we arrive, and use our ATM at bank machines as needed. Check with your bank to see if they have any foreign exchange fees. We actually bought more than we usually do this time when the Euro was at the $1.03 exchange rate a couple of months ago for our trip in September. Now it's back up to $1.12, so no need to get as much.