You don't have to do any changes in SDK. All you will be configuring auth keys in Marketing Cloud UI instead of certificates.
Using the steps in the same URL which you have provided in your question - https://org62.my.salesforce.com/sfc/p/#000000000062/a/0M000000OMhD/Ssu9rGuCZ7kc1aAvxGmqQGIhEK_hPvOxALWwdB9D1CE, change certificate to auth keys.
So, you can ...
Capacitor is not a platform we officially support, but I do know that customers are using it and we have not heard about any large blocking issues. Our upkeep of Cordova is minimal at this point but we do not have any plans to adopt Capacitor at this time.