I’m pretty sure that only made it appear with a lightbulb icon on the front end. The component is still part of the switch domain (and not light domain) and likely is still switch.xxxxx and not light.xxxxx.
To make a switch into a light, you have a few options.
The most universal option is to use the Light Switch Integration, which makes a new entity (a light) that turns on and off the switch entity that you already have. Just replace all of your refrences to the switch with the one for the light (including Lovelace front end, which will solve your initial problem of how it’s displayed).
Depending on what integration the switch is from, you have other options. Such as if it’s MQTT you can just change it from an MQTT switch into an MQTT light. If it’s ESPHome, you can define the output as a light instead of a switch. Etc.