I attempted to do what you are asking but with a 2021 install on the same server as 10.2 and I did not have a good experience - though I do not recall the details. While I have been told by support that it is possible, I ended up building out a separate VM for testing and will do that for any major upgrades in the future. Here is a recent thread on a related topic:
Best Practice For Major Release Upgrade? - Kinetic 202X - Epicor User Help Forum (epiusers.help)
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