I just read an article about www.airalo.com and checked it out. They offer data-only esims for much of the world at prices lower than I've seen from other online esim providers - e.g., 1 GB in the UK for $2, 1 GB in Germany for $2.50, 4 GB South Korea for $10.

As a test, since I am in the US, I downloaded a 1 GB esim valid for 7 days for $3. It downloaded easily to my Pixel 3A using the provided QR code.

It has a UK ip address, I can watch UK Channel 4 on the phone when using the esim. It uses the AT&T network. The phone shows that the carrier is Telna roaming on AT&T.

Speedtest results were 73 mbps down, 32.7 mbps up, with a ping of 329 ms.