VO2 max

Hej i'am new here,so here is my first question.

I'am 68 years old ,90 kg and 1.90 lengt,  and my VO2max is on my watch 31 and that is bad.

According to Google and ChatGPT my VO2max is good when it is between 30-35.

I use almost 2-3 times in the week VO 2 max ,the last 12 weeks.

I walk  every day 10 km and cycle alot.

My condition is ok.

Why is there a different between these two.

Thanks