You should regardless first aim to build out your Z-Wave network mesh as non-LR devices depends on mesh networking. Meaning that you just need to buy and add more mains-powered Z-Wave devices what act as repeaters which will extend the total range of your Z-Wave network mesh by connecting devices further away using other mains-operated Z-Wave devices as repeaters.
I recommend that you read my best-practices guide linked below on Zigbee network optimization as most of the generic mesh networking tips there also applies to Z-Wave because they both heavily depend on mesh networking, so if you do not only have Z-Wave Long Range devices you also need to build out your Z-Wave mesh network as well by simply adding more mains-powered Z-Wave devices to it. The guide also include other general tips on optimal placement and things that apply to all wireless devices because of how all radio signals work.