Let me sum up your last questions.
I had read that 9.5 U4 will be exchange DAG aware...but it seems I'm wrong ?
Yes Veeam B&R 9.5 U4 is Exchange aware. You can create managed by backup server job with the type failover cluster which was not possible before
Is it possible currenlty with veeam 9.5 U4 to backup exchange node and backup only passive database on each node ?
Unfortunately that's not possible in current version. Backup is created on the image level without additional exclusions.
Finally, what is changing in 9.5u4 regarding Exchange DAG ?
Before Update 4 the only option for DAG was to create a single backup job for every node and use job chaining to protect entire DAG.
I quite agree about the lack of Catalyst support for Agents - it's a dreadful hole in Veeam's coverage, given that the agents should hand them the market for backing up physical Windows & Solaris machines. And I can't even do a scheduled file copy job to a StoreOnce CIFS repo, never mind to a Catalyst store.
Catalyst support is planned and we are working on it.
Having to backup each database two times (or more if you have more that 2 copies) is absolutly inefficient
I agree that processing can be improved and will add all your votes to this feature request.