Determining the performance Impact of firewalld rule count

I was working on tweaking the performance of fail2ban and I read that a too-long ban can result in a build-up of rules that will negatively impact performance, which made me wonder, "Is there any particular idea of a number of rules that is 'too high' for nftables?" I currently use firewalld with nftables as the backend, and maybe 10-20 rules. However, a few servers are specifically intended for audiences of certain countries and should not be accessed outside them. If I pull down a country-IP database (e.g. MaxMind) and then generate a list of rules for all CIDRs for countries outside the allowed list, I end up with nearly 17,000 rules. On one hand, that's a lot of rules (IMHO), but on the other hand, there's nothing but spam and hack attempts coming from outside the designated countries (even legitimate users traveling abroad need to VPN into the US before they can access anyway). Is that kind of volume going to negatively impact nftables? I assume that the impact is relative to the amount of volume that has to be checked, but I haven't found a good way to see or measure the impact of the rules, and I don't want to start loading up thousands of rules without knowing the possible ramifications ahead of time.