Installing access panel in drop ceiling with spotlights for wiring

I live in a property that has a dropped ceiling. The original ceiling is a foot (or several) taller than the ceiling I see. Within that ceiling, there are spotlights. I have removed a fitting to poke in a telescopic camera (low resolution imagery/mobility of the head so quite hard to tell exactly what's in there) to get this information, and I can see there are timber lengths that presumably support a plasterboard ceiling, where the spotlight fixtures rest. I can't clearly see any other major electrical details. I would like to wire this household with data cabling (CAT 6, Ethernet) from room to room, to support my ceiling-mounted WiFi mesh network nodes. I have a tech background, but not a trade (electrical, construction), or DIY background. I want to install an access panel into the ceiling to be able to gain access more easily to work with what I have, but I don't want to cause any damage to cabling for the lights (safety) or structural damage. Are there any recommendations to tell where I'm installing the panel that won't hit obstructions, or lighting wiring, or otherwise? Are there specific tradespeople I should contact for this work? A plasterer seems off. An electrician maybe. But it's a mix of both.