I recently built an simpler kvm/ip using a few pi pico's and ms2130 chips. https://www.modularkvmip.com doesnt matter what server you use. Its not opensource but its just usb device passthrough at the core.
I have a lot of astro users. But you need to use Ethernet for the connection between VirtualHere server and client and not wifi. A pi5 is very good for this.
Yes generally i reject any request if its customization just for one customer. I try to generalize the change by e.g adding an API call. Also i get requests to keep xp/win7 support which i reject often.
The biggest thing I learned is to basically do nothing on the product, unless its needed. I used to be tempted to change things/add features for fun and for a challenge but its a mistake. The reason is it might introduce bugs. Too many customers and big companies rely on virtualhere now day-to-day and the software is complex enough that its hard to tell if the bug was always there or just from the new addition. Im very relucatnt to even upgrade the compiler unless i have to for a new OS etc.
I have run my one-man business for 13 years now. https://www.virtualhere.com . Back then I saw the market moving to the cloud and thought bringing device access there was needed. There was no one really doing this cheaply and easily. I posted a link to my software on the raspberrypi forum when that board came out and started getting my customers immediately that way. It took a year to write the initial software. Ive been adding updates and features ever since. I have made several million dollars in profit since then and its still going strong. I dont really have any competition at my price point .
I started https://www.virtualhere.com about 10 years ago, it provides a good income. I developed/sell/support everything myself. I felt there was a need for this type of product 10 years ago and with cloud computing/gaming its become very useful for a lot of use-cases now.