so to answer your question, yes it is possible to always have another block template available, one that does not depend on the transactions confirmed (or not!) in the previous block. 

available in stratumv2 pools that allow for block template creation + tx sets

bitentrepreneur

bitcoin

Empty blocks and improvement ideas

C_Otto

Future Jobs
An empty future block job or speculated non-empty job can be sent in advance to speedup new mining job distribution. The point is that the mining server MAY have precomputed such a job and is able to pre-distribute it for all active channels. The only missing information to start to mine on the new block is the new prevhash. This information can be provided independently.

Such an approach improves the efficiency of the protocol where the upstream node does not waste precious time immediately after a new block is found in the network.  


source: https://github.com/stratum-mining/sv2-spec/blob/main/05-Mining-Protocol.md#514-future-jobs