Yes, that was the proposed format, initially. Apparently, it hasn't been finalized and there are discussions to make it 12 groups of 4. They could end up using both formats as was done in 1982. That World Cup began with 6 groups of 4. The top two teams advanced into the second round which had 4 groups of 3. The top four teams of those groups then advanced to the knockout stage semi-finals.
I like the 4 team group format. The one drawback is that there is a potential for two teams to collude to keep another team from advancing whilst playing the third game. It has been questioned before. That question was also raised this year as to whether Spain intentionally lost to Japan to keep Germany from advancing.
From what I have read this week, any plans that were announced about 2026 can still be changed. There were only going to be 10 matches total played in Canada and Mexico. That may increase.