Williams team principal James Vowles says he "didn't sleep for days" developing the new car ahead of the new Formula 1 season.
Speaking at the team's livery launch in New York, Vowles said: "I wasn't sleeping for days - the weight of 1,000 people falls on your shoulders."
The team finished an improved seventh in the constructors' title last year following a fallow period in the sport.
The FW46 car will be unveiled at testing in Bahrain on 21 February.
Thai-British driver Alex Albon said they must "make good steps" after tweaking the design of their car.
"We're hoping to build on our progress," said Albon, 27. "We've asked a lot of the team and we've slightly changed the philosophy of the car."
The once-dominant Williams showed signs of recovery in 2023 after years racing one of the slowest cars on grid as costs soared in the sport.
Albon finished a season's best seventh at the Canadian and Italian Grands Prix in the FW45 car.
He added: "We've been working hard to make some good steps forward in performance.
"I'm interested to see if we can improve some of the characteristics it has historically had. It will require an adjustment in driving style but I'm confident it will be a change for the better."
Williams cannot be restrained by 'fear of failure'
Vowles, formerly chief strategist during Mercedes' most successful period between 2014 and 2020, added that the Mercedes-powered team needed to "push the boundaries".
"I made it clear to the organisation that the weight of failure rests on my shoulders, and don't want anyone else to be restrained by the fear of failure, or anyone to be restrained by the fear of pushing outside the boundaries of what they're comfortable with, " the 44-year-old said.
"Now is the time, and you have my support, to break from what you know and go back to the fundamentals and start again."
Albon finished 13th in the drivers' title last year with 27 points following a season in which he qualified fourth on the grid at the Dutch Grand Prix.
Albon out-qualified team-mate Logan Sargeant in all 22 races during the American's first year in the sport, in which he struggled to keep pace with Albon, who enters his fifth season on the grid, having previously driven for Toro Rosso and Red Bull.
Williams are in their fifth season of ownership under US investment company Dorilton Capital following the sale of the team by Sir Frank Williams and his family.
The team first competed in F1 in 1975 and enjoyed several periods of success through the 1980s and 1990s, which included seven drivers' championships - one each for Britons Nigel Mansell in 1992 and Damon Hill in 1996.
Frank Williams died in 2021 after spending much of his life in a wheelchair as a tetraplegic following a car accident in 1986.
Sauber launch new C44
Swiss team Sauber launched their new challenger for 2024 on Monday evening - the C44.
Sauber, renamed Stake F1 Team, have retained drivers Valtteri Bottas of Finland and China's Zhou Guanyu.
The team had been branded for the past five seasons as Alfa Romeo, and will continue to run a Ferrari engine as a legacy from the involvement of one of the many brands from the Italian Agnelli family.
In 2026, however, when a number of new changes relating to engines are introduced, Audi will take up their partnership with Sauber.
Sauber have been competing in F1 since 1993, from their Hinwil base in Switzerland, following a number of collaborations over the years, including a successful period with BMW in which the team won the 2008 Canadian Grand Prix with Robert Kubica.