At 100 kph constant speed you should be able to get just 200 km in range with a plus (21.5 kWh) Energica model. There are some remarks here in place though.
It will likely mean you run the battery close to empty, and as of 20 % or so output is limited so not very safe to use on highways. For that alone I wouldn't recommend it.
Empty also means you went passed the 30% SOC barrier of a fast charge back up to 80% at full 24 kW. If you charge for longer than 50% of the battery capacity (around 20 min) on high speed chargers you'll get into 40°C battery temperatures reducing the charging speed a lot. This blog post shows that lower ambient temperature is ideal (not for the rider but for the battery) if you need multiple charges on the road
https://fotoleer.wordpress.com/2022/01/08/running-my-energica-ss9-electric-motorcycle-in-the-cold-for-almost-400-km-and-3-charges-checking-battery-temp/On this image (from that post) you can clearly see the temperature peaks of the 3 charges I did. This was a 400 km highway ride BTW. You can also see the battery temp go up from the 12-14°C in garage to a perfect 25°C while riding at speed (in the cold).
Another important remark is that in ideal charging situations you get around 16 kWh from that battery, nowhere near 18 kWh. With a 14.4 kWh zero you would get around 12 kWh. I haven't tested any of their new models or their 110% charge features yet.
You can get a lot lower charge result just by charging in colder conditions. I don't know what season you test rode but 100% isn't always the same Wh available. For Example during winter my non heated but insulated garage ambient temp is around 12°C while at the office it would charge with 23°C ambient temperature. That alone is enough to see a big difference in the usable capacity. I also have a post about those numbers
https://fotoleer.wordpress.com/2022/02/22/energica-battery-temperature-versus-usable-capacity-after-balanced-charge/The graph from that post (obv above 30 it won't be that linear)
These are numbers reported by the BMS after a 100% balanced charge, so not something I "think" the bike does. Plus it was confirmed (at least the 15,x kWh numbers at around 20°C) on multiple bikes. I'm a big fan of Energica and prefer it over the Zero I had in the past. This is also not bashing, just numbers and things to take into account if you go for it.
So best count with 16 kWh available. Consumption on non highway rides can be as low as 70 to 90 Wh/km. On highway speeds more like 120 Wh/km minimal unless you really try hard. And if you ride faster way more, no need to try hard for that.
Tucking in while riding can gain you up to 10% in range. Obv that also works on a Zero.