How did you even come up with the idea to get a recumbent bike in the first place? What are they like to ride compared to a road bike?
You are asking the wrong question. Would you consider riding a road bike and a hybrid or mountain or fat bike the same? Recumbent just describes the seating arrangement and there is as much variance as between the above types of “upright” bikes that I have mentioned.
As you go up the audax distances you’ll find it gets harder and harder to stay comfortable on a road bike. You’ll need padded shorts, you may need chamois cream, you’ll want padded gloves, you may get a stiff back, your neck may hurt, you may have have problems keeping your head up on really long rides, your bum may hurt, you need to keep moving the hands around to avoid pins and needles or them going numb etc etc etc. Recumbents solve all these issues so the only thing you get at the end of a long audax is tired legs, and no special clothing required.
But as I said above , there are many variations and designs and also personal preferences. There’s no standing up to get up hills when legs tire. So you need a different approach to preserve legs more spinning, less mashing.
Do enough audaxes you’ll see a wide range of bikes, some of which will be recumbents. You may even see velomobiles which are fully faired recumbent trikes.
I consider mine like piloting a fighter jet. It just carves through the turns and laughs at headwinds. I now also climb faster on it than my road bike after the leg muscles adapted in all the right places.
Beware though, riding a recumbent gives you a manic grin
If you ever get to ride or volunteer at PBP there is even a start group dedicated purely to recumbents and special bikes.
RAAM which is a coast to coast race across America about 3000 miles was won back in the 1990s on my make / model recumbent with its full fairing which can be bought separately. It was won in 5 days 1 hour, a record unbroken to this day. Average over those 5 days of 25 mph or something. That’s an average including any stops.
A full fairing will add somewhere between 6-10 mph to your average speed.