Yes there is a setting to disable the creation of image posts. Don't worry too much about space usage - after 1 year of operation piefed.social is only using 20 GB for media storage.
For the blocked ports - look into using Cloudflare tunnels aka their Zero Trust product. It's free and very easy to set up. You just need a daemon running on your server which keeps the tunnel open and you configure it all from within the CF dashboard. Just remember to exclude the url "/inbox" from the WAF.
SSL is required but if you use Cloudflare they will take care of SSL for you.
You only need to send email, not receive it so your ISP won't block that. You'll need a SMTP server or AWS SES account. The free tier of https://www.smtp2go.com/ gives you 200 emails per day which should be plenty.
For more info please see https://codeberg.org/rimu/pyfedi/src/branch/main/INSTALL.md. Using docker makes it easier but it's still a moderately challenging beast to set up so perhaps not ideal if you have never self-hosted anything before. Good luck!