Server - Consolidate option handling, small refactors, doc changes

[MSP-Greg]

Description

Taken from PR #2373, added attr_writer's to maintain API, marked items as deprecated in v6.0.0.

PR #2373 included tests fixes. Those fixes will be anther PR, this shows that no API changes have been made that break CI here. I also double checked...

Small timing adjustment for a test that intermittently failed locally.

For one example similar to most of the fixes, see #2373 (comment)

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