Typical 2025 Ukrainian trench system: completely covered by even 2 meters of dirt, leaving only firing positions and entry/exit sticking out uncovered (anti-drone grates can be added to firing positions but are not always present).
This trench in particular was dug behind a natural obstacle, in this case the Yanchur river, and a barbed wire line was added right after the river later on.
This trench, while not completely camouflaged despite the similar color of the covering and surrounding dirt, is very sturdy and requires dozens and dozens of FPV strikes to even blast a small hole through, multiple direct artillery strikes or a direct FAB hit. Unfortunately for Ukraine, these trenches were and are mostly left undefended to Russian forces because of the lack of infantry to man them, and the Russians gladly accept them as mid-way accumulation points for further offensive operations, as if they were artificial settlements/basements.
Once again, I want to stress that even this way of building is not perfect, and would be only in the case of complete camouflage of the trench system inside a treeline or forest area. Camouflage is everything for a position: if you're found, you're automatically a target and you will, eventually, be destroyed.
If you're never found, you can't become a target in the first place, and even ambush attacking infantry under the right conditions.

The same video offers even more information: it shows a failed Russian flagging operation. Once again, I advise caution while mapping Russian or Ukrainian advancements by using flags: everything that moves in the battlefield is struck, and even the primary task itself of the flaggers is to record a video and retreat, and not to occupy a new position and definitely not to consolidate it.

Geolocation: https://x.com/ukrliberation/status/1990498077749465495
Source video: t.me/svarog_usf/551
Coordinates: 47.84848, 36.30634