1) You'll have to have a second SQL Server Instance (meaning another install), but the good news is that you can run multiple Instances on a single server. You'll just have to use a new Named Instance (i like "Sage2022")
2) The directions seem fine, though it's missing the first step: install a second SQL instance. When installing, I always use SQL Authentication to connect to the instances (it'll default to Windows Authentication)
3) You can do a MAS 90 Mode with Premium (see second section of
this page) though they still have the limit of only being in one at a time.
I find it very easy to get confused which SQL Instance you're working in, so make sure to have backup/snapshot of the databases and MAS90 folder before beginning.
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Steve Iwanowski, NextStep Technology Advisors, aka DSD Lancaster PA ¯\_(ツ)_/¯
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