I'm not sure if this is possible but it would greatly help for trading halls if there was an action that allowed for villagers to completely get rid of their AI except for trading and restocking. As villagers in trading halls are purely used for this, they are using way too much server resources by having their AI enabled.

I recommend using purpur and setting villager.lobotomize.enabled: to true in purpur.yml instead.
The customization options for purpur are disabled by default, and they have pufferfish patches too if you want your server to lag less.