Yeah, if you just you use it with the default reference consumption and the default advanced settings then it will almost always significantly over estimate consumption.
The default reference consumption (for most of the cars at least) includes a 10% buffer. (For example, for the i3 I set it to 3.8 or 3.9, and for the Kona I set it to 4.0 or 4.1).
Then, I just set degradation to 0 (the i3 has very low degradation generally, and the Kona and e208 I’ve had are brand new).
Finally, advanced weather and traffic speed settings are very important really and actual consumption could be wildly different from the predicted figure if for example there was a 10mph tailwind.
Before the premium version became available I used to use windy.com to get an idea of likely wind speed and direction and then enter something appropriate into ABRP. Temperature and precipitation settings need to be checked each time too.
And the traffic reference speed setting is (I strongly suspect) much more relevant if not using the premium version. If you have your max speed set at something like 72 but you are travelling in rush hour on a busy motorway, then you probably need to set the reference speed setting to something well below 100% as otherwise it will be assuming you are driving 72 for mile after mile when in fact you might only be doing 60ish. On the other hand, if you had max set at 72 and you’re on an empty motorway and actually doing 72 (gps speed) then the reference needs to be set to at least 103% to allow for the 2mph increase over the 70mph limit.
Then, when actually on the move and driving, I have my phone mounted (used a Brodit mount with magnetic plate attachement for the i3) and occasionally just check the predicted SoC against the actual SoC and adjust up or down in ABRP to match - then the consumption model for the rest of the trip will be adjusted accordingly and your arrival SoC will near enough exactly match the updated prediction.
In a car like the e208 with Tronity and ABRP premium this is all very easy because all of that is done for you - you literally just have to enter the destination.