The best retro gaming console is the one you already own.
As a former user of the original Retroid Pocket 2 I strongly disagree.
Many handhelds after that one improved a ton IMHO.
Currently I am settled for up to PSX games with my Miyoo Mini and my Anbernic RG351v, but I still want a more capable one, GCN, Wii and PS2 would be desirable.