It's very early — these were likely probing attacks looking to detect weak points in Russian defensive positions — but these attacks were much heavier than previous probing attacks.
We'll have to see what happens.
When the main offensive comes, it's very possible that Ukrainian forces will break through in certain areas. They might capture some territory (with plenty of U.S./NATO-supplied reconnaissance and intelligence to assist them), but it's unlikely that their gains will be sustainable.
The offensive will probably peter out as Russian forces gradually grind it down.
Russia has several defensive lines in the region, fortified by minefields, anti-tank ditches, concrete obstacles known as dragon's teeth, etc. These are formidable defenses that Russia has spent several months creating.
If Ukraine breaks through one line, it'll have to confront another. And another. And another one after that.
It's also important to realize that offensives on the scale envisioned require massive logistical support, and it's far from clear that Ukraine has the resources to sustain a major offensive. It doesn't help that Russia has been steadily targeting Ukrainian ammunition depots, transportation links, marshaling points, etc.