Upton missed Australia's victorious 2022 World Cup campaign after opting out with a calf issue late in the season.
The five-time NRLW champion will face New Zealand fullback Apii Nichols in Sunday's final at Suncorp Stadium.
Despite Nichols' form, Upton says she will focus on team momentum rather than a one-on-one contest.
"I'm on my own little island back there at fullback sometimes," she said when asked about Nichols.
"It's all about momentum, keeping them in their end, kicking the ball in a nice spot."
She expects New Zealand to target her similarly.
Upton said her body was fresh the following year and sitting out had been the right decision.
"But you do get a bit of FOMO (fear of missing out) and you watch them go over there and kill it."
"Obviously it sucked, but it was probably the best thing for me."