I'm not entirely convinced, and I will tell you why

Why Hilde doesn’t make sense as the Mole in this task:
1. Risk vs. reward
Hilde took a major risk by switching the suitcase. But the amount in the suitcase (€800) doesn't justify the risk. If you’re going to take such a risk, you’d expect a more significant result.
2. Too many unknowns
The task had many unpredictable elements—there was no guarantee Hilde would be the one to make it to the end.
If someone else made it with her suitcase, they could simply choose to keep the money once they saw it was a high amount.
3. Her actions didn’t match a Mole desperate to reach the end:
If Hilde's goal was to reach the final stage, she didn’t act like it. She left at a point where switching the suitcase would’ve been practically impossible.
During the question about countries, she wasn’t the one to say “Thailand,” which was the correct answer that allowed them to move forward—Sarah said it. If Hilde were the mole and wanted to control the outcome, she should’ve ensured that all country names were correctly given. Instead, she passively relied on others. If Sarah hadn’t answered, they might have failed—and the suitcase switch would’ve been pointless.
4. The mole’s main goal is to lose money, not to avoid suspicion:
A mole’s primary objective is to reduce the pot—not to protect themselves from suspicion (especially suspicion from viewers, because how do you know that she said anything about her suitcase and 800 euros to others?). Worse still, this move didn’t even reduce suspicion—she’s still being suspected by some viewers

So if it was a strategy - it failed.
The suitcase switch to 800 euros, had limited impact, too much uncertainty, and didn’t even lessen suspicion. All things considered, it’s highly unlikely that Hilde is the mole based on this task.