At the moment, there is largely stalemate across Ukraine. In some areas e.g. Bakhmut, it is clear that Russia are throwing bodies into the meatgrinder to make marginal gains. I imagine Ukraine casualties here are pretty high, given there isn't a huge amount of defence from artillery and Russia have so many men there. However I think it is extremely obvious that attacking a good defensive position with unsupported and inexperienced troops will lead to a significantly higher casualty rate for Russia. There are plenty of videos supporting this, with Russians advancing in open fields and being easily taken out.
There is clearly a reason why Ukraine needs tanks. With Russia dug in and Ukraine unable to break defensive lines with the current weather/ weaponry, Russia can afford to push their soldiers into a smaller number of positions for tactical, marginal gains. Breaking through less-defended Russian lines would force Russia to reassign soldiers to other areas, blunting their ability to attack Bakhmut, and given what we’ve seen earlier in the war significant Russian retreat.
I think you're overestimating Russia's position. According to pretty much every expert, the current war is a protracted war of attrition, with some unknowns around future Russian air power and Western government resilience. Bahmut may fall, but this line is moving metres rather than miles each day, and so a month worth of gains could be wiped out with a single, effective counter-attack. After giving Ukraine further NATO weaponry (i.e. tanks and air defence), which surely is the current base case, most experts expect Ukraine to seize significant momentum.
That doesn't mean the war will be over quickly. But it should ramp up the pressure on Putin from Russia's far right, whilst giving Ukraine a significant morale boost (and vice-versa for Russia).