thanks zach, I was starting to feel crazy
Let's say that the required functions are 2, similar to each other, but substantially different.
Let's start with the first.
Use outbound gateway when direct sending fails.
as you rightly said, it would be nice to be able to set the number of direct attempts before trying with outbound gateway. In order to avoid using outbound gateway when it is not needed. I'm thinking for example of when the first send fails because the destination server has a greylist or because it is temporarily unreachable. I don't know if it is possible to distinguish between a hard error and a soft error. In short, let's say that he should use outbound gateway instead of doing the bounce.
I imagine this setting both at the single domain level and at the server level as a general setting. which could then be a single outbound gateway or round robin
Here is a domain settings level image that I would expect
The other issue instead concerns the routing rules which I imagine as a real routing rules menu which must act at the SMTP and delivery level.
Here the rule should allow you to set.
if the sender is @domain.tld and the recipient is @outlook.com use this outbound gateway
This thing is different from the previous one.
Imagine that Outlook has blocked our server's IP. There is no point in triggering the use outbound gateway rule when direct delivery fails. Better not to attempt new submissions until resolution.
Furthermore, these rules can also be used in other contexts and for other purposes.
Considering that outbound gateways are often paid, using them sparingly and in case of emergency would be the best thing.
The possibility of using regular expressions should also be included in the rules.
These two options would make SM a complete system in my opinion