Client Hardware - how thin can you go?

Infosec  Actually, I don't see a single solution at the moment which is why I made the post. My volume is the 100's and it is within the Healthcare domain where kickbacks are a compliance risk.  We have to avoid 'do business with us and get a free computer' and the way that is handled today is loads of lockdowns (e.g. intune/endpoint manager).  That works but it is costly.  You have to pay for the software and the people to manage it.  Our goal is not to eliminate staff members, we want them to work on better things instead of lockdowns and machines.  We would like a low-cost device that can't be used for anything useful other than connecting to Windows 365.  The devices we've found seem to fall into three categories:

1 - too expensive and nearly the cost of a small stand-alone computer (e.g. Dell Wyse). For example - https://www.dell.com/en-us/work/shop/wyse-endpoints-and-software/sc/cloud-client/thin-clients $400 and up, may as well get a low-cost PC.

2 - Low-cost PCs can make the cost low enough, however, now you are stuck doing local device management.  We would like a truly 'throw away' device that can stick the back of a monitor or under the desk and provide just the connectivity needed.  Run only RDP, require no administration, be disposable. 

3 - What comes close, is a Raspberry PI device, however, our testing with Teams has been mixed.  Teams work best when able to use the acceleration for VDI capabilities.  This so far is our closest match.

Anyone else thinking this way?