It seems to me that Biden is spending a lot of money on new bills, and from my understanding of economics this means that government debt will greatly increase. Has Biden ever talked about this during his presidency, and if so, what has he said about this topic?
During the campaign, Biden was observed being the only Democrat candidate to speak about the debt or deficit at all, but only did so in the context of an attack on the tax cuts ushered in by the Trump Administration and Republican majority Congress.
In general, both parties abandoned deficit spending as a campaign issue - in no small part to the fact that the campaign was happening during a global pandemic that was wreaking havoc with the economy. Generally speaking, government debt load is measured as a percentage of GDP, but under pandemic conditions, the GDP figure is heavily distorted away from normal operating levels.
Generally speaking, those who advise the president have taken the position that government debt is less of a priority right now than getting the economy back on track; interest levels are at historic lows and are expected to stay there for a while, making borrowed money very inexpensive.
Indirectly, Biden has repeatedly taken the explicit position that the danger under current conditions is "doing too little," rather than doing too much. That is to say, he views austerity as highly dangerous while the pandemic remains uncontrolled, and government debt to be far less dangerous.
From a finance perspective, this is sound reasoning: having a low debt load doesn't do you a bit of good if you never recover from whatever is preventing you from making your budget, whereas a high debt load may still be serviceable if taking it on allows you to escape whatever conditions are preventing you from meeting that budget. It's still far too early to tell how well the Biden administration is striking that balance.
In general, however, the national debt has never been a high-salience issue among voters, and has been growing less and less so. This is why candidates and officials tend to not discuss it explicitly.