Absolutely Not! While I shorten mine to around 8 seconds in order to accommodate this retention concern you are missing out on something far greater than a few seconds of watch time if you eliminate your endscreens... studio time.
One of the metrics that YouTube uses to rate the performance of a video is studio time. You are not privvy to this as it is not shown in analytics, but a video gets credit for how much watch time it garners from viewers even after the video is no longer playing. This is referred to as Studio Time, though it is a rarely discussed and fairly secret portion of YouTube's Search and Discovery systems (the 'algorithm').
So for example let's look at this scenario. You have two ten minute videos. They both have equal 80% retention, but one has end screens to another ten-minute video that gets 80% retention and the other has no end screens.
The first video not only gets credit for the 8 minutes of watch time, it also gets credit for a total of 16 minutes of studio time. Because that first video is syphoning views to another video it is keeping viewers on platform and interested in the overall topic at hand, and it will be rewarded with more impressions as a result.