Can someone start a non EX / GX tournament on the forum, invite all of the players who are constantly crying about those cards and then proceed to crush their decks into oblivion with regular Pokemon ?
Luigi already said it: Your desired “casual” format can never work, no matter how many arbitrary restrictions you create. The core idea of any trading card game is the solemn fact that a small percentage of cards will always outperform the rest. Why would you spend money on buying boosters, in order to get that sweet Ultra Rare card, otherwise ?
You don't lose against GX / EX Pokemon, because they are OP, you lose because your decks are badly constructed and you are likely a rather bad player, which is totally fine, as everyone started from scrap at some point. It doesn't matter if you want to play relaxed and casual, or trying to get the highest win rate possible, if you don't want to improve, then you can only blame yourself.
Maybe TCG games aren't your cup of tea, in that case you should just quite the game. It's your free time, spend it on doing something you like and don't force yourself to play a game that you don't enjoy.
The shadows of the abyss are like the petals of a monstrous flower that shall blossom within the skull and expand the mind beyond what any man can bear, but whether it decays under the earth or above on green fields, or out to sea or in the very air, all shall come to revelation, and to revel, in the knowledge of the strangling fruit - and the hand of the sinner shall rejoice, for there is no sin in shadow or in light that the seeds of the dead cannot forgive...