I asked that do we need to set a slab (for e.g.: if we need to take in transactions with fees not less than 200 sats/byte and not more than 600 sats/byte, do we need to (or can we) put it like 200 - 600 sats/byte transactions to include transactions within the mentioned slab only)?

As well, if this is the case and we are allowed to choose our own size of transaction according to the protocol and decide not to include those low-fee/byte transactions, will they ever confirm?
Isn't it considered as monopoly spam attack by the miners' end itself to make the whole network and mempool congested in order to make everyone helpless and unwantedly give higher fee?