Koh Samui Thailand vs Da Nang Vietnam last week of May

Hi! I always get great recs from this community so hoping to ask. I'm in the Philippines and have 1 week before going to Indonesia.

I was thinking of either going to Koh Samui/Ko Tao or Da Nang, Vietnam and am torn between the two . Its for the last week of May. The flights from Manila to Da Nang to Bali seem a bit easier, but I've never been to thailand or vietnam and these seem the best 2 spots for May/June weather. A lot of philippines felt loud with motorbikes and touristy and I want to get back to a bit more authenticity and calmness

I'm worried that Da Nang is going just to be another city that is loud and require me to take a lot of transportation and I wont be able to relax, but I've always wanted to go to Vietnam

Koh Samui/Ko Tao

• pros: scuba Dive, relax on nice beaches, peaceful/calm, more nature?
• Cons - expensive, logistically not as easy to get to, never been to thailand so not sure if they are worth it

Da Nang:

• Pros: easier with flights, More culture, can do a day trips to Hoi An, maybe go to a tea farm, still has a beach
• cons: Beaches maybe arent that nice? Could be a loud city? etc.

Thanks for any help!