I got the thicker parklon mat (m15) same as little wiwa's mat thickness. My LO have been doing tummy time and lying there since 2months. Little wiwa, wandermat, parklon - depends on what design you like.
I use non branded playmats bought from shopee that are 1.5-2cm thick.
https://www.facebook.com/ChildrenMummies/ can check it out
You can consider Little Wiwa playmat which is quite thick
Parklon is good. There's different thickness to get
I'm using little wiwa mat. It's good and thick.
I just got a random playmat from online