It’s a really personal thing. Make a list of things important to you and how you use your headphones. At home or while traveling? Over ear or on ear? What type of music?

I got me a pair of B&O’s for at home use. Now I’m traveling more so I need noise canceling but that’s not the best in my pair so I’m looking to upgrade just because my use case has changed.

You didn’t supply us with any information to help steer you in the right direction so take a couple of minutes and think about it a bit

I use AKG 550s; find a pair and have a listen, you won't be disappointed.

https://www.audioadvisor.com/prodinfo.asp?number=HMSUSVARA

Why do you return the ones you've tried? What's wrong with them?

I have some Sony WF-1000XM4 and they're ideal for me, wireless, excellent noise cancelling, sufficient audio quality for the money. With sound gear there'll always be something better for more money and less convenience, depends how much of an audio snob you want to be if the market leader's offerings around the £300 mark aren't good enough for you.

Over ear or in ear?

I paid 79.99 for my JLab buds 3 years ago and they have never failed me. Still work perfectly

Good Over Ear Cups = One Odio A71 ($35)

Good In Ear Buds = Skullcandy Ink Plus. ($15)

And they are good to my particular tastes, sure some fancy $300 thing might be better, but I'm more concerned with "bang for buck."

I bought a pair of Sennheiser 280 HD Pros in 2007, they lasted me way up to 2016 -- the only thing I needed to be able to keep using them was to buy replacement Ear Pads and a fresh new Headband on EBay.

Need more details on what types of ear/headphones you want. Does it need to be wireless? Does it need to have anc? But anyway https://crinacle.com/ Its mostly for iems/headphones but worth checking though