You can split a survey into multiple pages, the questions on the next pages can be controlled by answers on previous pages.

Dear Alterbrains team, how can I create a poll where each question appears on a new page? I would like to create a poll with the following rule: 1. selection options 2. forwarding each selection to a new question 3. summary of the selection with a new question 4. result from selection 2 and 2 summar...

... helps to use HTML instead of plain text for report column headings. ⋅ Feature: backend menu item types. ⋅ Feature: multiple filters in backend reports view. ⋅ Change: PHP 7.4 as min. ⋅ Feature: repeatable page header and footer for PDF.   Read ...

Unfortunately, it's not possible out of the box.

Potentially, it's possible to create the pseudo "common survey" and next manually merge all submissions/answers from multiple suvveys into it by mapping each "common" question to similar questions from multiple surveys.

⋅ Fix: uploaded files are lost on submit of invalid survey page. ⋅ Feature: new setting "Multiple User Submissions Usergroups" to allow multiple submissions for specific usergroups only. ⋅ Feature: new permission rules "View Own Submissions", ...

Only all menus and menu items can be shared.

Also, contents on some of the subsite may increase considerably, should I expect performance issues on all the portal if using a single installation?

Sure, it's same as running multiple sites.

... which the actual content can be different on each subsite. Please check this case study, you can have single Joomla website which is loaded via multiple domains: https://alterbrains.com/joomla-extensions/administration/multisites-manager/case-studies/subsites-with-minor-differences-in-menu-items-and-or-modules ...

... Possible, survey permissions can be adjusted to allow survey for logged users only. 2. Save survey and continue later Possible. 3. Text answer + Multiple File Upload Possible. 4. Radio option answer with sub-question (example: if users answer "Yes", they will need to answer another ...

... like to know if this extension can do these features : 1. Private survey (must register first) 2. Save survey and continue later 3. Text answer + Multiple File Upload 4. Radio option answer with sub-question (example: if users answer "Yes", they will need to answer another sub-question ...

... like '-30 day'. ⋅ Feature: custom date format for Calendar filter. ⋅ Fix: 'select all' link doesn't highlight all options in multiple-select dropdown filter. ⋅ Fix:  issue with  /* IF filter_tag = 'value' */  condition statement. Read full article...