Quite likely that Trump thinks he can force Ukraine into a one-sided peace deal by lying about the effectiveness of Russian forces. A strategy that's ultimately no different than what Biden was doing. Just – in usual Trump fashion – being implemented in a much more heavy handed and overt way.

The truth is, Ukraine can absolutely defeat Russia by force. This pisses off a lot of scumbags in the west who have made tons of money off of trade with Russia. But it's a much better option than the alternative of yet more invasions and war.