Last year's Sweden winner Rovanpera expected a tough fight opening the snow-covered roads as the best-placed of the full-time WRC drivers at the previous round in Monte Carlo.
Rovanpera was able to show flashes of speed to score six stage wins, more than another driver, but could only finish fourth after losing a fight with Hyundai's Thierry Neuville.
The 22-year-old ultimately finished, 25.1s behind eventual winner M-Sport's Ott Tanak, who claimed a solitary stage win.
The reigning world champion particularly struggled for speed on the second pass of stages that had become rutted. At times Rovanpera was critical of his car's set-up and was also lucky to reach the finish after a rare wild spin on Stage 13.
To further outline the situation, Rovanpera even elected not to push to win the powerstage to ensure he wouldn't have to start the next month's visit to Mexico first on the road, dropping to second, three points behind Tanak in the championship standings.
Rovanpera wasn't the only Toyota driver to struggle as teammate Elfyn Evans was unable to reproduce the pace that put the Welshman in the victory fight last year, while Takamoto Katsuta, set a fastest time in Stage 4 before damage sustained from a roll on Stage 5 contributed to his retirement.
Asked if he was concerned by the struggles this weekend, Rovanpera told Motorsport.com: "I'm not really worried, we were in the fight quite well. Definitely, if we didn't have this road position we could have been better.
"It has been quite a difficult weekend but in the end we can be fairly happy.
"[There is] not too much [we can take from finishing fourth]. "We can take that we need to improve. The second pass in these conditions we lacked the pace. On the first pass we were always in stage winning pace but it is not enough we needed to do it in the second pass.
"It was clear that everyone would be much closer than last year."
Heading into the weekend, Toyota had only been beaten in Sweden once since the marque returned to the WRC in 2017, when Neuville triumphed for Hyundai in 2018.
Reflecting on the result, Toyota boss Jari-Matti Latvala added: "This was certainly a rally that we were hoping to get something more from, given that it has usually been a strong event for us in the past.
"We suffered a bit on the first day when the conditions were not ideal for our road positions and those starting further back were able to attack and build a gap. We tried to fight back and speed-wise I think we saw some positive signs, but things just didn't quite click for us in the end."
