You could have paid more in fees if you wanted to secure a spot in the mempool. Its all about whether you want to pay more to be first or be patient waiting while paying less. They accept my transactions just fine, I just offer a bit more in fees to get my stuff included in the block.
Claiming its the fault of "spam" either shows you don't know how Bitcoin and fee markets work or you are just blinded by whatever Knots propaganda was presented to you. Also Core nodes don't have filters for blocking Knots nodes. It is the other way around Knots has the function to block OP_RETURN transactions which is actively censoring transactions that are valid to the chain.
My transactions were also just UTxO consolidation as well and it still got into the block. I just had to offer more coins in return to get a spot in the block.