I believe bitcoin core wallet (bitcoin-qt) is a
Type-0 nondeterministic wallet. For example, the Bitcoin Core client pregenerates 100 random private keys when first started and generates more keys as needed, using each key only once. This type of wallet is nicknamed "Just a Bunch Of Keys," or JBOK, ...
Quoted from
Mastering Bitcoin by Andreas Antonopoulos
So, with bitcoin-qt, you could generate as many private-public key pairs and associated addresses as you wish.
Mind that as you spend generated 100 keys and start next 100 key batch, you need to back up the wallet again.