Hi Peter,
This is no legal advice! You must ask a Microsoft representative if you want an official Microsoft statement.
For questions regarding pricing/licensing, please get in touch with a Microsoft sales partner or licensing expert.
Call (1-800-426-9400), Monday through Friday, 6:00 AM to 6:00 PM PST, to speak directly to a Microsoft licensing specialist.
My personal opinion on your question:
According to the SQL Server 2019 license guide, you just need a server license for each SQL Server and additionally one (!) CAL license for each accessing user... doesn't matter which SQL Server that person is connecting to.
Each SQL Server CAL allows access to multiple licensed SQL Servers, including Standard Edition and legacy Business Intelligence and Enterprise Edition Servers.
I hope my answer is helpful to you,
Your
Bjoern Peters
If the reply was helpful, please upvote and/or accept it as an answer, as this helps others in the community with similar questions. Thanks!