There is no really strong definition of “fascism” as an ideology.
The Nazis, for example, had a tendency to just make shit up as they went along when it came to economic matters, and as for religion - well, that depended on which Nazi you talked to (Himmler was “into” bizarre mystical neo-paganism for the SS, Hitler himself thought that was pretty cracked - but didn’t step in to put a stop to it).
Really, they were a sort of grab-bag of popular early 20th century notions - “scientific racism”, eugenics, nationalist mythologizing, futurism, oddball occultism, anti-Semitism, cult of the great man, popular social Darwinism - all mixed together in various combinations and often, like Spinal Tap, ‘turned up to 11’; Mussolini, for example, wasn’t as big on anti-Semitism as the Nazis, until pressured by Hitler.
What unites all these things?
I’d say, above all, the notion that society should be run by a self-selected group of the most ‘fit’, chosen exactly because of their ruthless cunning, and lead by a ‘great man’ who is the most ruthless and cunning of the lot; that in effect might makes right; that no-holds-barred competition is a positive good - both between societies and in choosing the group of leaders and the ‘great man’ to lead overall.
The great man and the self-selected grip of leaders under him have every right to order society as they see fit; to ensure its purity of thought and composition by eliminating despised minorities and works; to enforce their particular ideals and ideas on the remainder.
What virtue does this ideology possess?
Its advocates would point to nature; that it is, in effect, not hypocritical - it worships at the altar of success. The best become leaders, and we know they are the best, because they forced their way into leadership over the bodies of the less-best. Lead by the best, most competitive leaders, fascist society will then be geared for competition against other societies. If that competition succeeds, then that fascist society is best.
Fascist society (so the argument goes) is better than a democracy. In a democracy, leadership is chosen by the whim of the led. The herd only wants comfort and safety, not struggle and excellence. The herd doesn’t care if it contains the sick, the unfit, the lazy. The future belongs to the fascists, who will improve the stock by culling it; order the herd with vigor; and organize the herd to succeed against all comers.