Good day @Alessio Sammartino
According to your description, this issue is related to a specific version of the SQL Server Management studio (SSMS) and not to the SQL Server. If as you said, you can run it using SSMS 18.x and not using SSMS 19.x then you should report it as a BUG in the Microsoft feedback system here: https://feedback.azure.com
The direct link to report SQL Server or SSMS issues it here:
https://feedback.azure.com/d365community/forum/04fe6ee0-3b25-ec11-b6e6-000d3a4f0da0
Note! It is HIGHLY recommended to check it using Azure Data Studio (ADS) instead of SSMS: