I imagine that users also will have multiple orders in their lifetime.. so you would only want to count the visits since their first purchase / previous purchase / first ever visit, correct?
This kind of logic is complex... to be honest, I would probably ask our Data Team to calculate this from our Data Lake (where we process the Raw Data Feeds) and they have access to full SQL logic...
I will try and think about this... but it's tricky... cause you have to isolate just the visits between last purchase and current purchase (for repeating visitors), but then you also need to see the number of visits since the first ever visit to the first purchase...
Trying to use Adobe's sequential logic doesn't necessarily look at last to current order instance... if you were to use something like "Order THEN Order" it might look at first order to second order from all time, so then you would have to add a lot of extra checks and balances to try to isolate the recent purchases... and that I am not sure offhand how to make the logic return correct data....