Selenium is still relatively easy to detect by JS, but on the other hand it does require some dedicated[0] effort even if just the user-agent is overriden and that itself might be enough to work for relatively long time. Other important thing is rotating over different IPs that appear realistic[1]

[0] dedicated in a sense of lets include some script specifically designed to detect Selenium. [1] for example it's kind of unlikely that non-bot visitor is using IP from a range used by amazon instances. not sure how often this is used but I assume that most bot-detection systems would use that information at least as one of the metrics