So the Russian army sent unmanned tanks to Syria

“(T)he Uran-9 complex is not capable of performing the tasks assigned to it. In particular, in carrying out of combat missions, the average range of sustainable management from the advanced control point was 300-500 m in the conditions of the settlement with low-rise buildings, while also were recorded 17 cases of short-term (up to 1 min) and 2 cases of long (up to 1.5 hours) loss of Uran-9 control.

“The low reliability of the running gear elements – supporting and guiding rollers, suspension springs is revealed. The chassis of the Uran-9 cannot be used in ground close-combat roles for a long time and requires field repair.

“During a study of reconnaissance capabilities, it was revealed that the electro-optic stations allow reconnaissance and identification of targets at a range of no more than 2 km. The OCH-4 optical station does not allow detecting optical observation and targeting devices of the enemy and gives out multiple interferences on the ground and in the airspace in the surveillance sector.

“There were also cases of unstable operation of the 30mm 2A72 automatic cannon – 6 delays and failure. The UGV provides fire only from the site, which significantly reduces its combat capabilities (armament, sighting and reconnaissance devices are not stabilized).

“As a result, it was concluded that the modern Russian combat UGVs are not able to perform the assigned tasks in the classical types of combat operations.”

https://defence-blog.com/army/combat-tests-syria-brought-light-deficiencies-russian-unmanned-mini-tank.html

Link at http://www.woodpilereport.com/

However: “Uran-9’s combat experience in Syria revealed serious problems with the system. That having been said, the UGV was not a vital part of the fighting and the whole point of sending the systems to a combat zone was to expose flaws that might not show up in peacetime. Uran-9 might be a failure, but the concept itself is promising. If Russia’s defense industry can fix the problems Moscow could have a dependable, lethal robot on its hands and a real threat to NATO forces.”

https://www.popularmechanics.com/military/weapons/a21602657/russias-tank-drone-performed-poorly-in-syria/

The best place to test a war machine is in a war, particularly a war that does not involve a large part of your military.