Others have pointed out that we/Biden don't have to choose only one, but there's a reason to juggle multiple priorities too. In car sales, they use (or used to, it's thankfully becoming less common) a technique called four-square. Breaking the negotiation into trade-in price, total price, down payment and monthly payment. They work on one, trying to reach an agreement (that benefits them) but if it stalls in one box, move to the next. As you reach agreement in more boxes, it's easier to get the other person to settle for less/more in the other boxes.
In politics, if Biden decided to tackle only one issue, Republicans will mount an all out defense, think Affordable Care Act and how many people still hate it (or think they do) and ultimately what passed was a small fraction of what we wanted. Still better than nothing, but the right wing noise machine is getting better at creating frothing rage.
So instead put Ukraine, Tuition forgiveness, Gun Control, Border Control, and Minimum Wage on the table at the same time. When one stalls, and right wing media has people too whipped up about it, move to the next. Saner minds will multitask better than the permanently angry and hopefully when it all shakes out (we need a budget soon) we get more of what we wanted than if he only focused on one.