Having seen the video of the lawyer, Alfio D'Urso reading out the affidavit, this is my take.

D'Urso is definitely a lawyer and it's definitely him reading out the affidavit. It doesn't appear notarised nor to have been filed anywhere in Italy in any kind of official capacity.

But what does the affidavit actually say.

It would be strange for someone from Naples (Arturo D'Elia), supposedly involved in international espionage, to ask a commercial lawyer like D'Urso from a completely different region (Sicily) to represent him.

In fact D'Urso makes no claim to actually be representing D'Elia. The affidavit is signed by D'Urso, not D'Elia, and what D'Urso declares is that he has been told this information in "several meetings with a high level army security services official."

D'Urso is reporting what has allegedly been told to him, not D'Elia's direct words.

In fact there are some obvious errors in the affidavit. D'Elia was never Head of IT for Leonardo, and although there is a satellite facility in Fucino, "Fucino Tower" doesn't exist. Which furthers the argument that D'Urso is reporting second or third hand claims, and isn't actually connected with D'Elia.

The affidavit claims that D'Elia gave explicit testimony in court, but there is no evidence of this and if true hasn't been reported at all in the Italian media.

So why would D'Urso make these claims.

Firstly we don't know who this "high level army security services official" is. Assuming they exist at all, we don't know their motives or the reliability of the information. For all we know it could be Flynn.

D'Urso could be being fed misinformation (and all he is swearing is that certain information has been relayed to him).

If the official exists at all they could be Italian or they could be American. In 1970 it's alleged that rogue elements within the CIA, (as well as the Sicilian Mafia), supported or tacitly approved a failed right-wing coup d'etat in Italy, so international interference would not be without precedence.

https://en.m.wikipedia.org/wiki/Golpe_Borghese

Secondly we don't know D'Urso's motives. It seems strange a commercial lawyer, not representing D'Elia, would be privy to the deepest levels of international espionage.

Again, the document does not appear to be filed anywhere in Italy in any official capacity, but was apparently sent to Congress on the morning of the 6th.

Italy has a dark past of corrupt links between business, politics and organised crime. The P2 scandal is the stuff of conspiracy theorists' wet dreams: secret masonic lodges, mafia, corruption at the highest level of politics and the Vatican Bank - but it's not conjecture, it's a matter of historical record:

https://en.m.wikipedia.org/wiki/Propaganda_Due

So it's not impossible that someone in America called in a favour from D'Urso, asking him to send the affidavit to Congress on the day of the vote. Or maybe he was just paid a chunk of money; perhaps that explains Lin Wood's crazy too.

Again, D'Urso isn't really compromising himself, all he's doing is swearing that certain information has been reported to him by an unnamed Army security official.

The supposed involvement of Matteo Renzi, a left wing politican, who stopped being PM in 2016 and who's party commands 5% of the electorate is particularly suspicious. Renzi is unable to win any elections in Italy, so it seems laughable he can control the US elections. No Italian can seriously picture Renzi as a shadowy overlord. But he's disliked by the Italian right. It's almost as if they threw his name in while they were at it to throw mud at someone they dislike, although it detracts, rather than adds to the theory's credibility.

To believe the theory is true we have to belive:

D'Urso is telling the truth, in so far as he was told certain information by an unnamed official. This is possible, perhaps even likely, but it's still strange why a random commercial lawyer in Sicily would be privy to this.

The security official is real (possible or likely) and is accurately reporting what D'Elia stated (IMO unlikely, not least because the affidvit cites inexistent court testimony and contains factual errors about D'Elia's employment and Fucino Tower).

Assuming that D'Elia made these claims in the first place (IMO unlikely, but we can't check because he is behind bars on unrelated hacking charges) that they are true in the first place (IMO very unlikely - not least because of the hyperbolic claims that "more votes were given to Biden than registered voters" - if this was true it would be easily confirmed, but in fact paper ballot totals match the dominion numbers.

TL:DR D'Urso is real, but he's a commercial lawyer with no direct contact with the alleged hacker, reporting 2nd or 3rd hand information.

My money is on either:

Someone from America called in a favour from D'Urso, to send the affidavit, hoping to influence the vote on the 6th.

The "high level army security official" is real, but possibly playing D'Urso for their own reasons.