Car rental Rome

I've not rented in Italy. However, when in Europe, I use AutoEurope. It is a consolidator that handles most of the rental companies, the pricing has been great and their customer service excellent.

When I rent in Italy (every year, pandemics permitting) I also always use www.AutoEurope.com based in Portland, Maine (although the company was founded in Germany). In 2019 I rented for 5 weeks while in Italy, so almost as long as you plan to stay.

It’s a wholesale broker that works with the main car companies operating in Europe like Europcar, Avis-Budget, Hertz, but the pricing is always better than going directly with them.
https://en.m.wikipedia.org/wiki/Auto_Europe

I recommend selecting the “zero deductible” option in the “insurance coverage” section of the website. It costs less than $5 extra a day, but I prefer it for my peace of mind since the deductible is often €1000 to €2000 and it doesn’t take much to rack up that much even with a minor dent.

I just cancelled the car I rented thru Autoeurope for my France/Spain trip. I called them. Took about 15 seconds and the rep was very pleasant. I already have a confirmation of the cancellation in my email. Can't beat that for customer service

We prefer to book with AutoEurope as well.
Just a head's up regarding your proposed 41 day rental: some rental car companies only allow a maximum rental period of 28 days, and their policies may vary by country. I don't think Europcar has any restrictions, but we did run afoul of that rule with Hertz several years ago during a lengthy visit to Ireland - thought I was all set for a 2 month rental only to be told while standing at the desk that I'd have to break it up into two one-month rental periods. We were able to sort it out without too much drama, but having to modify our plan on the fly wasn't a particularly enjoyable beginning to our stay in the country. Point being that you should read the Terms & Conditions carefully when booking to ensure that you don't have an unpleasant surprise at the rental car desk when you collect your vehicle.

If you plan to rely to any degree on insurance coverage provided by one of your credit cards, check on that as well. There may be a time limit there.

Leasing is often recommended for rental periods over 30 days, but I think the leasing companies operate out of France, so picking up a car in Rome might not be possible. It would be worth a quick Google, though, because I think there can be substantial savings on insurance costs when you rent. (All this based on things I've read; I've never rented a car in Europe.)

Auto Europe does leasing in Italy - not sure of the rates/terms - see this link: https://www.autoeurope.com/long-term-car-rental/

Also happy with Autoeurope and it’s excellent customer service. When the rates dropped we called and had our price adjusted several times. But you have to track and make the call.

https://community.ricksteves.com/travel-forum/italy/car-rentals-italy-sixt-vs-ryanair
https://community.ricksteves.com/travel-forum/italy/car-leasing-italy

What did you do in 2017?

car rental recommendations in Rome for 41 days

Are you planning to be "in Rome" for the '41 days' ?