Has anyone tried a Lightsail Ubuntu instance for Wordpress

While I don't have specific user testimonials, I can provide some insights based on the information available about Amazon Lightsail and WordPress hosting.

Lightsail does support Ubuntu as one of its Linux distributions for instances, and it's possible to run WordPress on these instances. The $7 Ubuntu instance (which is likely a t3.small) could potentially work for a low-traffic WordPress site, but its performance might be limited compared to the optimized Bitnami WordPress instances.

The Bitnami WordPress instances on Lightsail are preconfigured and optimized for WordPress performance and security, which can be advantageous. However, as you've noted, they can be more challenging to update and customize.

Using an Ubuntu instance would indeed offer more flexibility in terms of selecting and updating PHP, MySQL, and other software versions. This could be beneficial if you need specific versions or want more control over your environment. However, you would need to handle the WordPress installation and optimization yourself, which requires more technical knowledge and time investment.

Regarding memory concerns, the $7 instance might be sufficient for a low-traffic site, but it depends on your specific needs and the complexity of your WordPress setup. If you find that you're running out of memory or experiencing performance issues, upgrading to the $12 Ubuntu instance could provide more resources and potentially better performance.

It's worth noting that Lightsail offers the ability to create snapshots of your instances. This means you could try setting up WordPress on a $7 Ubuntu instance, test its performance, and if it's not sufficient, you could easily upgrade to a larger instance size using a snapshot.

When considering this switch, also keep in mind the security aspects. You'll need to ensure you're following best practices for securing your WordPress installation on Ubuntu, such as configuring firewalls, keeping software updated, and potentially implementing additional security measures.

Ultimately, the choice between a Bitnami WordPress instance and a self-managed Ubuntu instance with WordPress depends on your technical comfort level, the level of control you need, and your specific site requirements. If you're comfortable managing the server yourself and value flexibility, the Ubuntu option could be a good choice. However, if you prefer a more managed solution, sticking with or updating to a newer Bitnami instance might be more suitable.
Sources
Community | Securing Wordpress on Lightsail: Hardening Wordpress
Community | Securing Wordpress on Lightsail: Lock Down Your Server
Virtual Private Server and Web Hosting – Amazon Lightsail Resources – Amazon Web Services
Instances - Amazon Lightsail