Why aren’t the Russians using better soldiers or equipment in Ukraine?

Russian forces seem to be using old or outdated equipment during their invasion of Ukraine along with poorly trained conscripts. Some have suggested that the Russians use these troops as cannon fodder before elite troops engage. Others have considered this to be a Maskirovka or "deception" and Russia is holding its elite troops in reserve to take on NATO.I served an an OPFOR or "Opposing Force" unit in Germany in the 1990's and we used Russian equipment and tactics to train NATO forces.