I suggest sticking to common dictionary words when naming your lights. My smart plug lights are named: bedroom light, chair light, study light. Names for my other smart plugs are kitchen, humidifier. Alexa has no problem identifying each plug.
I like using routines with my plugs as my commands can be very brief. “Alexa, evening” turns on my chair (living room) light. “Alexa, bedtime” will turn off my living room light, turn on my bedside lamp and turn on my bedroom humidifier. “Alexa, goodnight” will turn off my bedside lamp and Alexa will say goodnight.