The idea among Texas Democrats is that the more people that vote, the better it is for the Democratic Party -- and a huge turnout would translate into turning the state blue. It didn't work out that way though.
In the 2020 election, a record number of voters went to the polls. About 11,223,990 people voted (about 66.2% of registered voters). The previous record was 8,969,226 in the 2016 election. That means the record was smashed by more than 2 million votes. But it did not turn into a win for Democrats in the presidential (or Senate) race.
Demographics are changing Texas, as whites become a smaller portion of the population with each passing year. The k-12 school population is already majority non-white. Eventually, this will turn the state blue as the GOP continues it racist and white privilege protecting policies. But we are not there yet.
The 2020 election shows that Texas is still a very red state.
The numbers in the chart above are from the office of the Texas Secretary of State.