Hi there,
Thank you for your review! I’m sorry to hear about this issue, even though it wasn't related to us. 🙁
I’ve checked your support ticket, and from what I can see, you confirmed that the issue wasn’t related to us but to your hosting provider’s CloudLinux memory limits.
”I’ve checked this with my hosting provider, and they confirmed the errors were caused by CloudLinux memory limits (PMEM) killing the PHP worker during processing. They have since increased the limit, and optimisation completed normally.”
The firewall issue was also related to your hosting provider, and this can happen with any image optimization plugin that uses servers. Because you have many images with multiple thumbnails, numerous requests are needed to optimize everything. Some firewalls are more sensitive and may temporarily block some or all of our IPs. This can be easily fixed by whitelisting our IPs, as my colleague mentioned.
Credit consumption per image depends on the number of thumbnails generated by your theme and WordPress itself, so usage varies based on your thumbnail count. We have a thumbnail exclusion system that can help you save credits by skipping unnecessary sizes. More information here.
As for PageSpeed scores, they generally improve when you generate and deliver WebP/AVIF images, as shown in this article. However, depending on your theme and hosting provider, additional optimizations may be needed to improve scores further and those factors are outside our control as we already mentioned within the support ticket. My colleague offered to log in and help configure the settings and check this for you but you haven’t provided access.
I find this review a bit unfair since the problems weren’t related to our plugin, and we still did our best to help.
Also, from what I can see you also left this review on TrustPilot after I already answered your review on Wordpress.org and offered to help which doesn't seem fair.
We’re still happy to work with you and get everything related to WebP/AVIF configured perfectly so you can have a great optimization experience. Just reach out whenever you’re ready, we’re here for you! 🙂