How do you actually pick a mattress that won’t suck in 3 years??

So me and my girlfriend have been on the same mattress for around 6 years now and it’s pretty much done. There’s a dip in the middle and we both slide into it every night… used to be funny but smh not anymore

Last time we bought one we just tried a few in store for 5 mins and called it a day. This time I actually looked into materials, density, all that stuff and yeah… it gets confusing fast

One thing that threw me off is how many “organic” options still mix in different layers or materials. I was leaning toward an organic mattress thinking it’d be the safer long term pick, but figured I'd ask here first.

So now I feel like I’m overthinking it a bit. Any tips are welcomed!

Also, I don’t mind spending more if it actually lasts.