Link multiple forms to a single spreadsheet file

Nextcloud (please complete the following information):

• Nextcloud-Version: 32.0.8
• Forms-Version: 5.2.7

Is your feature request related to a problem? Please describe.
No, it is not related to any bugs that I am aware of.

Describe the solution you'd like
When linking form submissions to a spreadsheet, provide the option to link form submissions to a new sheet in an existing spreadsheet file/workbook. This would would allow multiple forms to be tied to a single spreadsheet/workbook file, as desired.

For example: I have forms for tracking different health/fitness entries at different intervals. Forms for end of day data like nutrition intake and step count, weight, weekly body measurements, and weight lifting exercises. This data would be handy to combine in charts for further analysis and for sharing with accountability partners, fitness trainers, and medical professionals. Combining these form submissions into a single workbook would be less overwhelming for the people I share my data with and less work for me.

Describe alternatives you've considered
I have been doing this in Google Sheets for over a year, but my goal is to get away from Google now. For now, I am resigned to maintaining multiple workbooks and combining copied data from multiple spreadsheets to create reports for others as needed.

Additional context
N/A.

Thanks for all your contributions to NextCloud and Forms!

No files, tests, or entry points are identified in the issue. Start by locating the existing form-submission-to-spreadsheet linking flow and determine how workbook and sheet selection currently work. Done means multiple forms can target separate sheets in one existing spreadsheet file while their submissions remain linked.