Magsafe duo charger - apple watch charging takes a long time

Hello!

Recently I bought a magsafe duo charger both for my iPhone and Apple Watch Series 8 to be able to take both chargers anywhere I go. I use a classic 20W Apple adapter with the duo charger, but I noticed a big change in the time it takes for my Apple watch to recharge. Usually I put my apple watch in the morning when they are at around 20% and it took (with the original charging cable inside the box) like 30 minutes to charge to around 90%-100%. Now it takes much longer. Please note that I charge iPhone and Apple watch always separately - I never charge my iPhone and Apple watch at the same time on the magsafe duo.

It's kind of a problem for me, because I sometimes forget to charge them when I am supposed to go out and have to either wait long time to get atleast a few percent, or just leave them home.

That's not what I was expecting from a kind of expensive charger.

Can I make it charge my Apple watch faster? I don't mind my iPhone being charged slowly - I charge it in the night. Will a different, more powerful brick make it go faster? And if so, do you have any experience with a specific brick?