The fact that lawyers and the "lawyer system", in conjunction with prosecutorial offices and the police, has made this expensive and pretty impossible for 99% of people and companies is a huge problem. It basically nullifies the whole point of government as protector of people's rights and enforcer of laws.
Invalid takedowns don’t open you up to anything. The only risk to takedowns is misrepresenting the purported owner but that’s not the case here and the risk would be from Funko not Itch.
Much of the reason for DMCA abuse is that beyond the notice being assumed legitimate there is basically no risk to the complaining party until they dispute a counter-notification.
Not that this is relevant in this case, as it was not a DMCA takedown. A takedown notice would have been addressed to Itch.