There is a URL scheme call that will let you not only trigger Draft’s dictation, but allow it to be returned.
To me this sounds like something ideally suited to Shortcuts. It can access the camera, make x-callback-url calls (to utilise the dictation URL call above for example), and to make API calls - which is what would be required for Slack.
Assuming your ‘SOP “bucket” folder’ is accessible on your device via a storage provider, then Shortcuts can write to it. If it is outside the Shortcuts iCloud folder, then you will need to employ either a manual process to select and save each time, or utilise a Shortcuts helper app that supports folder bookmarking to allow you to do that automatically assuming the storage provider has been developed to support bookmarking - e.g. Toolbox Pro supports accessing such storage and iCloud natively supports bookmarking.
Slack I think is the one that’s going to pose you more of a challenge. You may not consider yourself a programmer now, but it is quite likely you need to develop a few programmer skills to wrap this one up.
RoutineHub is a place that people can share and post about shortcuts they have made using Shortcuts. I found a shortcut on there that works with Slack.
It uses the Slack API (Application Programming Interface), which is a way that Slack provides for other apps to communicate with the Slack service. But, note above that it is about posting text to a Slack channel. This means that you would need to build on that shortcut’s functionality to allow it to also send the image, which means digging into the API documentation at https://api.slack.com. I have seen someone ask for help doing this on the Shortcuts reddit, and while they do share an insight, they didn’t get any answers.
I think there’s pretty much everything you need set out above to do exactly what you want, but it isn’t trivial for someone to pick up from scratch if you have never worked with Shortcuts, x-callback-url, or an API before. In fact, I would say that even if you had, it would take a while, experimenting with how to get the image uploaded and appearing. The point is mainly that you wouldn’t have to start from scratch.
Fundamentally it should be possible and learning the required skills to put this together would open up a world of opportunity for you. The question is how does the need to accomplish this balance out against the effort of doing it. The age old automator’s dilemma.