We have thought about it but still evaluating. In general, our thought here is that in case we go out of business, customers should be able to continue using the software with access to source and some level of temp support. We'd codify these terms into contracts. From conversations with others, this seems similar to how companies like Plaid, Stripe and LaunchDarkly handled it, especially in the early days.
That being said, BSL/AGPL looks interesting but I'm not that well-versed in them so it's something we're going to look into more.
Be careful on licensing anything that gets linked/deployed in to the customers environment. There are many large and small enterprises with “strenuous review” policies, if not blanket bans, on licenses like AGPL. This is not to argue the morals or utility of those policies but it is fact.
Similarly it would behoove you to read on the “relicensing” issues of the last few years. Many companies start small with open source to drive adoption, then discover that business model also explicitly enables others to use the same work and compete in the same space. Much heartache ensues.
That being said, BSL/AGPL looks interesting but I'm not that well-versed in them so it's something we're going to look into more.