The 1stGTA and 4thGTD are Russia's "elite" armored formations. They get the best equipment.
4thGTD is mostly T-80U's and have lost about 1/3 of their tanks.
The idea that they would deploy their best units to combat with junkyard equipment is ridiculous.
Russia began this war with just under 3,000 combat capable tanks. About 1200 were upgraded since 2010. Ukraine had about 840, half of which were upgraded versions.
Russia has not sent everything they have to Ukraine, but right now Ukraine has more tanks in the fight than Russia does.