Best way to backup MSSQL in v13 with one instance excluded

[starwars1999]

Hi,

I'm just rebuilding the backup at a new customer and I want to restart with v13 and use as many appliances as possible.

One problem is the backup of the sql server.
There is one MSSQL 2022 server (single server, no always-on group, etc.) with 4 instances.
The first instance is in full mode but is not under my control - I have full access to the instance but I am not responsible for the backup at all (it is managed by an external software producer) but I have to backup their local backup files. The other three instances are in simple mode and should be backuped once a day.
I was thinking about an "application aware" backup job and exclude the one instance like it is described in kb2110 (https://www.veeam.com/kb2110): set a registry key and configure a global database exclusion. Is this the right way or do I have to exclude the database from SQL Log backup like described in kb2104 (https://www.veeam.com/kb2104)?
Either way has anyone tested it with the software appliance? Especially the part with the registry keys? After long searching I found kb4779 (https://www.veeam.com/kb4779) - so the official way would be, to download the "veeam_backup_and_replication.conf"-config file, add the value in the [root] section upload it und then it should work?

Greetings

Philipp