I believe the nature of the beast is such that it required a bespoke DTH to integrate it to SmartThings. The latest phase of the migration of legacy device handlers to current integrations is to move devices still using custom DTHs to the best available Edge driver. In this case there isn’t anything useful for it to move to so they use ‘LAN Thing’ which is pretty much a placeholder for the device. Why isn’t there anything for it to go to? Well I’m afraid that would have been down to you to have arranged over the last two years, even if you didn’t know it was.
Edge drivers can’t make http requests to the cloud so ideally the replacement would have been a cloud based integration rather than an Edge driver, though if you have suitable additional hardware there is a community solution for relaying the requests. In the latter case it may even be possible to build a solution by exploiting Todd’s Web Requestor. It rather depends on the detail of what your device does and the http requests it requires.
There seem to have been a few mentions of the Photon over the years, so perhaps others have already addressed the problem.