Elantra overdue for its major service, where do you take yours?

My Elantra has just crossed 80k and I've been slack with the servicing, I'll admit it. It's had oil changes but nothing major, and now I'm worried about the stuff I've neglected like the coolant, transmission fluid and spark plugs. The dealer is quoting a package that sounds comprehensive but also feels like it's padded with things I don't need. I came across an expert Hyundai maintenance garage serving Khalifa City and Musaffah and it got me thinking about whether an independent would actually be better for a straightforward car like this. My question is what genuinely needs doing at 80k on an Elantra versus what's just upsell, because I don't want to skip something important but I also don't want to pay for flushes the car doesn't need. Has anyone here done a major service on their Hyundai outside the dealer and been happy with it? Also, does servicing outside the dealer network cause any issues with the warranty if it's still valid? Would appreciate some real world input.