Great content and perspective. I would say (and fair warning, this is obviously biased as I run one of the investment banks that specialize in B2B SaaS M&A between $2-20M ARR - Discretion Capital), this:

"Now should you hire a banker when there is no actionable inbound interest and you have no prior relationships? I would recommend no, as in such a case bankers would typically rely on their network of Corp Devs and present your company to a laundry list of potential companies that likely have nothing to do with your space or business or you have no interest working for."

..is not how a great banker that actually does deals in the revenue size and market you're in would act. I can see how a "too large" a bank where you're small fry, would do this, but eg in my space ($2-20M ARR), the key job of your banker is to reach out to whomever would pay the most for your business, not just their corp dev buddies they happen to have existing relationships with.

That's not easy - there are 1000+ repeat software buyers with various portfolios and all kinds of timing constraints, and that's even before considering true strategics (in my range, the buyer mix is 70% PE or PE owned, 20% strategics and 10% other).

Typically, for a proper process, you'd want to see 100-150 (well sourced and properly targeted) potential acquirers. If they're just sending you to a handful of corp devs then they're not taking your business seriously and you should get another banker.