I auto-buy 300$ of VOO daily when markets are open, is this a bad strategy?

It’s a fine strategy but mathematically investing $9000 a month as a lump would be better. $108,000 at the beginning of the year, even better. Time in the market beats timing it. Now of course no one knows where it will go, but it is likely that the market will be higher on 12/1/2026 than it is today. So if you put $108,000 in today, you have the entire year for it to grow and benefit. By doing it daily it is fine, but you very potentially lose out on a lot of those gains between now and then as you’re averaging in rather than buying at the “low” price it is now. Again, the market could absolutely tank which would make your strategy better, but mathematically and historical data has shown the one time lump sum as soon as possible to be better.