In one Telegram channel (https://t.me/cryptoEssay) I saw a message from someone who develops two services for eSIM.

The first one is eSIMHub (https://esimhub.io), they offer one sim for 180+ countries with per-megabyte billing, cryptocurrency payment is available.

The second one is eSIM Quantek (https://esim.qntk.ru), they offer mostly the same, but they also have sim's for specific countries and for Europe.

If you compare these offers with Klook and other country- or region-specific eSIM services, then these two services have worse prices. For example, Klook offers Hong Kong sim with 1GB for 7 days and it costs just dollar and a half, while Quantek offers the same for 8 dollars. But if you compare it with other services that offer ~worldwide eSIM, then these two have better prices. Well, these services utilize very specific usecase and they can be useful for those ones who need one sim for many countries, while others can buy few sim's for specific countries and it will be cheaper.