As long as the machine can run Windows 10, it could use the RDP client (not the OLDER mstsc RDP client though). That means that machines that are up to around 9-12 years old should be able to be used as thin clients. But I do agree, it would be real nice if they could go back further than that.

You could even do upgrade to max RAM, change hd's to ssd's for old computers, install Chrome OS Flex, and then from there access your W365 clients. Just an idea

When it comes to users accessing large files on network shared drives that are on-premises, the experience can be influenced by several key factors: Internet Bandwidth and Latency: The performance of Windows 365 heavily depends on the quality of the internet connection. Since the system streams the desktop interface and data through the internet, high bandwidth and low latency are crucial, especially when dealing with large files. Cloud PC Configuration: The type of Cloud PC (specs like CPU, RAM, and storage) you choose in Windows 365 will affect performance. Higher specifications would typically handle large file operations better, though this also comes with higher costs. Network Setup: The configuration of your network, including VPN setups and direct connectivity options like ExpressRoute (which connects your on-premises network directly to Microsoft's network), can significantly impact file access speeds and reliability. File Synchronization and Streaming: Depending on how your network drives are connected and synchronized with the Cloud PC, there might be additional latency when opening or manipulating large files. Some setups might benefit from using Microsoft's OneDrive or SharePoint for storing and accessing files to leverage Microsoft's cloud optimization. Optimization Technologies: Windows 365 integrates with Microsoft's existing technologies like the Office suite and OneDrive, which may use file optimization techniques such as differential synchronization (only syncing parts of the file that changed). This can improve the experience when working with large files. User Density and Resource Sharing: In environments where many users are accessing cloud resources simultaneously, resource contention can occur. This would affect the performance of accessing and processing large files unless adequately managed. For specific use cases, such as graphic-intensive applications or when handling exceptionally large datasets, it might be necessary to conduct a pilot program to see if Windows 365 meets the performance needs and to make any necessary adjustments in the setup.