Flynax application is a very good industrial application for building multiple websites.
Possibility to create groups of user announcements, etc.

Unfortunately, this affects performance - many loops are very poor, e.g. for fields in categories
You can see that the authors are trying to save themselves with disk cache and this is a good solution and a good direction, but that's not all.
A serious problem is Samrty templates version 2.x which is a disaster for this application.
Smarty is good for construction, it is easier to build templates, but their performance is currently a disaster... currently smarty is already in version 5.0 and that is almost 14 years old.
And it should be added that the new version of smarty templates is also not a solution because they are also slowly.
Another issue is the creation of templates - they are nice templates, but when tested in Google Core Web Vitals they have the lowest indicators, e.g. 4/100 in CLP.

Currently, an application purchased in this way without any significant modifications has no chance of success.
The indicators in Google are so weak that even if the content is the best, it is disqualified by Google Search Console.

There is no full-text search engine and when ads exceed 50,000 words, the website is so slow that it is unsuitable for viewing.

I put a lot of work into ensuring that the website could have over 200,000 ads and high indicators:
Please see zoomia.pl

I have been using this application since 2010.
I also have the latest service applications but nothing has changed in terms of performance and smarts.

If anyone is interested in professional modifications to make the website work properly and quickly, I can sell several modules.

Artur