Unless it’s a super small scale evaluation, my recommendation would be yes - one server per app.
It will help with performance/stability and is generally just a best practice. If there’s a lack of available hardware that would stop you evaluating on more than 1 server, just go for it, but ensure by the time you’re moving out of evaluation you have more infrastructure planned.
If you were upgrading the legacy app to our new one, you might have run into the error below while trying to authenticate. We're still investigating the cause of this but here's a workaround...
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