We are currently using the force:canvasApp lightning component to embed an external site securely into Salesforce.
The Spring ’19 release is introducing Lightning Web Components as the future of Lightning development for Salesforce. If we wanted to convert our existing
force:canvasAppcomponent into the new LWC Model, what are my options? Is there a different way altogether to embed external sites securely into Salesforce with the new LWC Model?
Aura Components are not going to be deprecated any time soon . I raised this question on the twitter to the PM for canvas and LWC and here is the response from him , please check screenshot below
Hence for few more releases I think you will have to use the force:canvasapp and the aura bundle .