I would trust a battery gauge more than a normal fuel gauge.
Do EVs have LED lights by default? A pair of 60W halogen bulbs is a significant power drain (particularly in queuing traffic).
https://mpoweruk.com/soc.htmThere is a reason the SOC indicator is often called a guessometer, methods of working out state of charge or battery health are very tricky and not as accurate as people may think. Using battery terminal voltage may work quite well for a lead acid battery where battery terminal voltage is fairly closely related to state of charge, but for lithium chemistries that does not work so coulomb counting is used, which tries to measure what goes in and what comes out but as battery ages its capacity gets less, so this has to be factored into the algorithm, and anything that interrupts the measuring can result in large errors. One source of error is self discharge of battery which can give a higher reading for SOC than actual is the case. Also keeping Li-Ion battery chemistry in a high state of charge damages it.
I had a good example of coulomb counting going wrong on my electric razor recently when I replaced the Li-ION battery. I had checked the new battery voltage before installation and it was pretty much fully charged at 3.75volts - but after installation the shaver would not run, I had to unsolder battery again, connect a bulb across to discharge to 2.85 volts and then reconnect, after reconnecting the battery I then recharged it and the shaver ran OK and has done so ever since - the fact that the coulomb counting device was not happy meant it stopped the shaver running even with a fully charged battery simply because it had lost track of the battery charge / discharge history. I had no idea how much charge was in the battery after I discharged it, which means that the error is now fixed in the coulomb counter, it may say battery is empty and stop razor running when battery is still 30% full for all I know....
I would have thought LED lights all round would be absolutely essential on battery powered cars due to drain of filament lights.