No. That wasn't a low risk high reward signing. Just because a guy has a big season out of nowhere doesn't make it a low risk high reward signing.
If things went well for Perez, most people assumed a 2 fWAR season. Nobody assumed a potential 4 fWAR season.
At most, he was moderate risk moderate reward (risk being injury, wasted rotation spot due to ineffectiveness, contract above minimum etc.).
For example, if Judge signs a monster deal some where, it's going to be high risk high reward. If things go well, he'll hit close to 2022, but not necessarily match it.
If Franchy Cordero is DFA'd and claimed by the Marlins, the definition of him doing well would be everyday OFer. That would be low risk low reward. If he outperformed that level and has a near All Star season it doesn't make it a low risk high reward move. More often than not, these low risk low reward moves don't move the needle because the moves don't generate high returns, which is why they are all lumped together as low risk low reward. You can't just resort them after the fact.