Use Chronik instances strategy

[nghiacc]

To apply the new method to select the best strategy:
https://www.npmjs.com/package/chronik-client

List of public nodes:
https://chronik.cash

Also include our own chronik.lixi.app/xec

Ideally:

https://chronik.e.cash
https://chronik1.alitayin.com
https://chronik.pay2stay.com/xec
https://chronik.lixi.app/xec