Currently the war is at a stalemate, Without the help from Iran and North Korea. there would be no movement on the front lines. Russia has manpower, but precious little else in its favour. The first year of the war saw massive Russian incompetence, which resulted in the mauling of their experienced troops. They have lost 75% of their tanks, and significant amounts of Infantry fighting vehicles and artillery. This is why now most of their fighting is with Infantry (mostly untrained). Only the winter of 2022 gave them a breathing space.
The Russian military industrial complex is broken. Massive corruption means that factories are inefficient and missing many of the more sophisticated elements they need. Production of complex weapons happens at a snails pace, and doesn't keep up with the rate of loss. Infantry these days attack in civilian cars, ATVs, motor bikes and even on bicycles. As long as they are available, drones, artillery and mines take care of most of them. Successes are rare, but Ukraine has insufficient troops to stage major counter attacks. Russian losses are now believed to exceed one million men killed or wounded - because casualty evacuation is rare, mainly killed. Men have been sent into the attack on crutches!
Russian strengths are manpower, shahed drones, ballistic missiles and to a lesser extent, artillery. Glide bombs were a problem but are now less useful. Their 'meat attacks' result in heavy losses, but Putin doesn't care about Russian losses. However, the cost of this war is collapsing the Russian economy, inflation is at about 20%, and civilian infrastructure is not being maintained. If Ukraine can keep up its defence, Russia will probably run out of steam in 2026 - 1917 again? In 1916, Russia was having great success with the Brusilov offensive, which inflicted heavy losses on the Austrians and Germans. But it left Russia so weak that it's armies collapsed a year later.
Ukraine is now fighting a war of attrition. In defence, their casualties are much lower, they can trade a kilometre here and a kilometre there, but are bleeding Russia dry militarily and financially. But Putin is greedy, he wants everything, he may end up with nothing if he doesn't do a deal.
Tom Cooper's military blog on Sarcastosaurus has given a real insight to this war.