Going back to basics, you have to ask what are the benefits of crop. When introduced, the biggest was cost of sensors. You could decrease camera component costs by $300 versus full frame in the early days. You could also produce smaller, cheaper lenses of equivalent focal length. This made crop a great budget line choice.
Today, the component cost differences of an equivalent crop sensor versus full frame are in the mid-to-high 10s of dollars. And producing more, smaller, cheaper lenses makes less sense in terms of manufacturing scales today, even discounting the current logistics problems and shortages.
Now, the benefits of crop would be size and weight. I think the M mount cameras have a market that is more about the size and convenience of the cameras than anything else. A set of 5-7 lenses of the M mount size would make for a fine budget/small-size line, but it would be important to Canon that this new line provide and encourage an upgrade path to the R mount. This is what the M mount lacks. That the M mount has been given the Sony A mount treatment in the past couple of years is highly indicative that Canon agrees.
Logic would have Canon eventually release an R-mount equivalent of the M line, but to do so starting well in to 2023, after manufacturing issues have cleared. The line would have 4-5 lines making it a whole system sometime in late 2024. An R7 doesn't really fit into this conceptual picture unless it is purely to stratify pricing.
