Find PHP version being used:
> matt@example:/etc/php$ tail ynh_app_version
> castopod:8.0
Update `memory_limit` in `sudo nano /etc/php/8.0/fpm/php.ini`
Restarted PHP 8 service, getting `504 Gateway Time-out nginx` now. Progress?
Then set `client_max_body_size` in here to 700 rather than 600:
`matt@example:/etc/nginx/conf.d/castopod.example.net.d$ sudo nano castopod.conf`
Then set `max_execution_time` to 90 at `sudo nano /etc/php/8.0/fpm/php.ini`
Restart nginx and PHP services (I used https://example.net/yunohost/admin/#/services).