That is, simply storing 51% of the total amount of Bitcoins on the wallet will not help to make an attack? Do you need exactly 51% of the capacity of bitcoin, computing machines that ensure the operation and security of the network?
Miners need to own 51% of hash power on the network and maintain it for a while in order to do 51% attack. It is very costly if you have to hire hash power from any source and many full nodes will detect suspicious things. They will switch to other pools and the community will have solutions to stop the attack.
You are wrong because hash power is needed to run attack. Not Bitcoin. Miners need of have ASICs, and they don't need to have Bitcoin to confirm Bitcoin transactions.