Airalo provides at least "full speed" LTE in all their destinations. I've not experienced 5G myself but can confirm I got wicked fast speeds on LTE... certainly more than fast enough to do anything I would possibly need on my phone including iOS updates. But let me unpack "speed":
- Throughput: Airalo in my experience has provided unthrottled full speed LTE. Fastest I got in Italy & Germany was over 300mbps. Average between 50mbps - 100mbps
- Latency: Latency is where airalo isn't as good as a local sim. In Europe, I averaged around 75ms pings on airalo. Which is pretty damn good, but not as good as a local. In contrast, at&t and t-mobile roaming averaged around 300ms pings as all traffic from them is routed through a US APN, whereas airalo was routing through someplace in Europe.
All in all, for MY needs whilst traveling I don't need 5G type speeds if I can regularly get 100mbps speeds over LTE. Ironically this speed is WAY better than any hotel premium wifi I paid for, or any other wifi I could find in Europe. Between my cheap-ass relatives in germany's crap wifi and the crappy hotel wifi (even premium) I got the impression ALL the wifi in Germany, Italy and Austria sucks balls. Hell I was even on the guest network of the world's largest Chemical company in Germany (BASF) at their Ludwigshafen headquarters, and it topped out at a measly 10mbps. I ended up using my eSim data nearly exclusively.
The speed difference certainly wouldn't justify the hassle of hunting down a local physical sim and wasting precious time on my work or leisure trip for that purpose. Your mileage may vary.