I think you're confusing the chronology of two separate events (or rather, whoever told you this did). During WW2 there were two separate uprisings, the Warsaw Ghetto Uprising and the regular Warsaw Uprising. These were separate uprisings by separate people, over a year apart.

The Warsaw Ghetto Uprising began in spring 1943. At this point the Soviet army was nowhere near Warsaw. Forgive my foggy knowledge of the military aspects of WW2, but the battle of Stalingrad had been the previous winter, and the German military, while halted, was by no means defeated or anywhere near it. The front was raging hundreds of miles east of Warsaw.

The Warsaw Ghetto uprising was not initiated because it made military sense. The ghetto was about to be "liquidated", i.e. the remaining inhabitants were going to be sent en masse to be murdered. The ghetto had long existed with constant "deportations", which over time it was increasingly clear meant near-certain death. Many of those remaining opted to fight rather than die willingly. At no point was it particularly likely the revolt would "win" in the sense of actually defeating the Germans. The goal was mostly to delay "deportation" as long as possible by making it difficult or impossible for the SS to remove people from the ghetto. While there was some assistance from the Polish Resistance, the revolt was mostly by home-grown Jewish resistance groups. While there was some assistance, the state of affairs for non-Jewish Poles was simply not dire enough to make that sort of last-ditch rebellion at this point worthwhile. It was unlikely it would actually win, and Poles were not facing mass-murder if they didn't revolt immidiately.

It is often claimed that the Warsaw Uprising involved the Soviets halting their advance. The Soviet Army was close by but did not advance into Warsaw while the Germans put the revolt down. Not being my area of expertise, I can't comment a whole lot on the motivations behind it or the reasons for the revolt or for the halt of the Soviet advance. But, the point is that for the Warsaw Ghetto Uprising, the claim doesn't make any sense, since the Soviet army was nowhere near Warsaw, and no one had the expectation that the would or could aid the Warsaw Ghetto Uprising, unlike the Warsaw Uprising where the front was much closer.

FWIW I have heard people claim this about the Warsaw Ghetto Uprising before. It fits neatly into some of the narrative around Jewish resistance during the Holocaust, which makes that sort of thing you described in the OP more believeable to a lot of people. But it's not right, the Warsaw Ghetto Uprising was well before the Soviet army was anywhere near Warsaw.

This is related to a more general incorrect assumption, that the Holocaust stretched the duration of the war. 1939-1945 is an easily-remembered time block for the war. And we hear about the Holocaust from people who survived it, and the worst of their experiences were generally from the late 30s or 1941 to 1945 when they were liberated, which matches up neatly with the duration of the war. But, for most European Jews, the Holocaust ended earlier, because they never lived to see liberation. The revolt was in early 1943 because that was basically the end of the line for Jews there. The mass shootings were in 1941 and 1942 mostly, the death camps operated mostly in 1942 and 1943. During 1943 a significant proportion of the death camps were actually decommissioned, since their intended role in killing the bulk of European Jews were complete. Some continued into 1944, and of course people still died from disease and overwork and execution outside death camps. But the height of the genocide ended long before the Soviet Army swept through Eastern Europe. The timescale of the Holocaust was related to but separate from the war. This is the reason why the two Warsaw revolts were separate. The Warsaw Ghetto Revolt was timed based on when the remaining Jews of Warsaw were going to be killed, which was very separate from the timeline of the war going on outside.