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Unfortunately, it's not possible to "easily" modify currently existing renewal configuration files, for example to add a deploy hook (post-hook is probably not the best hook to be used here by the way). IMO this is a very big issue with certbot currently: not being able to reconfigure an already existing certificate without going through the whole issuance process again.
The goals of getting certificates with an ACME server are to automate the workload so you won't have to take any any manual steps to renew a cert-- including reloading your web server. I think it will be worth it to test and re-issue a certificate such that that the renewal config gets updated. The whole issuance process is relatively quick and your server seems to be in good shape for renewing/issuing certificates. Also, one or two extra certs while you work to get the best set-up is a drop in the resources used bucket for Let's Encrypt. But, definitely use staging if possible!
For now then, @greatl-lancer will likely want to use the --force-renewal parameter along with a --deploy-hook "nginx -s reload" or possibly -i nginx (but be careful with that one if you've modified your port 443 server block).