Using KWin's window tabbing feature, we can make rekonq emulate the behavior of chromium by opening new windows instead of tabs within the same window. This will not however allow each window of rekonq to crash independently – all windows of rekonq crash as a single process. It merely emulates the look of Chromium, giving individual controls for each web page you load.
Click on the Tools menu button and open the Configure rekonq dialog. Click on Tabs. Unselect all options to disable all tab handling in rekonq. Now, rekonq will always open new windows instead of tabs.
Now, we'll set up KWin to automatically tab all rekonq windows together. Head to → . Select Window Behavior on the left and go to the Advanced tab. Here, under Window Tabbing, check Automatically group similar windows. Click Apply.
Now, rekonq will open windows by default which will automatically get tabbed together.

rekonq configuration

System Settings configuration

The result