Hugo, as you can read from the posts above, 100,000 tracks is not an especially “large” library. The performance problems you are seeing are likely to be caused by some other factor(s).
The organisation of album folders can possibly be a factor. Many people organise them by Artist / Album (probably because this is the default organisation used by many ripping applications), but having them in alphabet folders should not be an issue. Something else is going on I suspect.
Your best course of action, rather than tack your question onto an old discussion is to open a new support request in this Support category of the forum. The Roon Support team prefer one topic per customer’s issue… so they are able to track it and focus on each individual problem.
In order for Roon’s Support team to better assist you, please provide a brief description of your current setup and the nature of the issue using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so they have a clear understanding of how your devices are connected. Thanks.