Hi @Brian-Parkes and welcome to the community 🙂
Compete resources are only rarely provided publicly, I know only these resources applicable to Microsoft 365: https://www.microsoft.com/en-us/whymicrosoft365?activetab=tabs%3aprimaryr3
Of course there are legal reasons that such content needs to be handled with care and thus often can not be provided freely, but this is not the only reason these are not being shared broadly - I think the much better and more sucessful approach is to be confident in and focus on presenting the Microsoft solution value.
Compete-plays are nice to have, but I think no customer can be ever convinced to decide in favor of one solution just by making other solutions look bad.
Or in other words - we encourage Partners to show the customer how the Microsoft solution can help fulfill business needs & requirements instead of focussing on comparing with competitors.
If any comparison of vendors is helpful, I personally think it is a report from an indepent 3rd party, so some useful content can be found in the published analyst reports: https://dynamics.microsoft.com/en-us/analyst-awards/ & https://news.microsoft.com/analyst-reports/
And finally - as a Partner you can open a PreSales request to get guidance for a specific customer project, this may include also compete content - and if you have an account team assigned at Microsoft (Partner Development Manager) you can of course also contact them.