Beyond the default Firefox browser hot keys anything other then that is either addon or 3rd party apps to make those changes.

For Mac, the article still lists Control + Return:

https://support.mozilla.org/en-US/kb/keyboard-shortcuts-perform-firefox-tasks-quickly#w_miscellaneous_2

So it should work. However, there is a setting to disable it. Could you check:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button accepting the risk.

More info on about:config: Configuration Editor for Firefox. The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.

(2) In the search box in the page, type or paste ctrlCan and pause while the list is filtered. Firefox should show one match (please ignore the line with Boolean Number String).

(3) If the browser.urlbar.ctrlCanonizesURLs preference has a value of false, double-click it (or click the Toggle button or Reset button at the right end of the row) to restore the default value of true

• If you changed that, any improvement?
• If the false comes back after your next Firefox restart, we need to help you hunt down the culprit, possible a user.js file.
• If it shows a lock icon at the left and cannot be changed, we need to help you hunt down an Autoconfig file or possibly an Enterprise Policy.

Hi, I had checked browser.fixup.alternate.suffix already but rechecked and it is set to true. I changed it to false and back to True but I still do not get .com appended. I am on 136.0b7 (aarch64)

What about browser.urlbar.ctrlCanonizesURLs ?

also set to true

Jscher you were thinking correctly on this. But it appears the latest MacOS Sequioa release has stolen the Ctrl+Enter shortcut for itself to open context menus so Firefox can't use it. I tracked it down to this bug: Bug 1945422 - Ctrl+Enter keyboard shortcut in the address bar no longer adds "www." and ".com" to the address bar string on macOS

The patch with the new keyboard shortcut, Cmd+Enter, has not been added to Beta yet but it looks like it will very soon. The developers also plan to update the old shortcut to the new one in the KB article you found Jscher.

Notes from the bug: MacOS Sequoia introduced a new default shortcut to open a context menu: Ctrl+Enter. This conflicts with address bar shortcut to complete search string (e.g. "example") to .com URLs. We are changing the shortcut on MacOS to Cmd+Enter. The existing pref browser.urlbar.ctrlCanonizesURLs is named after ctrl, though we think it's not worth changing it, as that would break existing resources pointing to it, and it's quite common on the Mac to replace ctrl with cmd in general.

[Suggested wording]: Due to recent changes in MacOS Sequoia, the shortcut to complete search strings to .com addresses has been changed on MacOS from Ctrl+Enter to Cmd+Enter. The preference to disable this feature, browser.urlbar.ctrlCanonizesURLs, was not renamed, and it's valid across all the supported platforms.