When using Symfony's web profiler, the performance of the dashboard decreased in 4.6.1 compared to 4.5.4 because the \Ibexa\Bundle\DesignEngine\DataCollector\TwigDataCollector::lateCollect() has much more to do in 4.6.1 than in 4.5.4, see screenshots (higher durations for 4.6.1).

4.5.4

4.6.1

Additionally data from the twig profiler view:
4.5:

• 630 ms Render time 
• 354 Template calls
• 772 Block calls
• 595 Macro calls 

4.6:

• 1318 ms Render time
• 605 Template calls
• 1295 Block calls
• 897 Macro calls

Note:
Issue is not necessarily a bug - but worth to check for possible improvements.