Improvements pertaining to the handling of multi-experiment creation

[opcode81]

• [X] I have added the correct label(s) to this Pull Request or linked the relevant issue(s)
• [X] I have provided a description of the changes in this Pull Request
• [X] I have added documentation for my changes and have listed relevant changes in CHANGELOG.md
• [X] If applicable, I have added tests to cover my changes.
• [X] I have reformatted the code using poe format
• [X] I have checked style and types with poe lint and poe type-check
• [ ] (Optional) I ran tests locally with poe test (or a subset of them with poe test-reduced) ,and they pass
• [ ] (Optional) I have tested that documentation builds correctly with poe doc-build

Description of changes: see individual commits; should be merged without squashing.

Co-authored by: @maxhuettenrauch

Partly addressed #1129