Is my Infiniti due for a major service or can it wait?

I bought my Infiniti QX50 used about eighteen months ago and I honestly have no idea what servicing was done before I got it. Since then I have just been doing the basic oil and filter change every six months at a garage near my place in Abu Dhabi. The car is a 2018 model and the odometer is sitting at around 85,000 km now. A colleague at work mentioned that I should probably be doing a major service at this point but I am not sure what that actually involves or whether it is really necessary. I have been looking for a quick comparison of minor and major service for Infiniti drivers because every workshop explains it differently and I want a straight answer. What actually gets done in the major that makes it worth the extra cost? How do I know if the previous owner already did the major service before selling? Is there a way to check the service history through the dealer or does that only work if it was serviced there? Also does skipping a major service cause real problems down the line or is it something that can wait a bit longer if the car feels fine? I do not want to create issues for myself but money is tight right now and I need to prioritise. Any honest advice would really help me decide what to do.