Is it possible to mix the two types? We also had a lot of existing concrete (basically the patio connecting to the house. The pool was installed in front). Thought we'd have to either stick with additional concrete -making it a massive concrete park- or tear it all out like the paver installer suggested. There was also significant level changes which would be hard to match. In the end we used Belgard pavers for the new pool deck and kept the existing concrete, using mexican beach pebbles in between the 2 types to not only provide drainage into hidden drains but transition the types. Works beautifully and we are glad to have a distinct look.

I used Houzz pool photos a great deal to get ideas. For example this pool setting uses a lot of different types! [Infinity-Blue-contemporary-pool-sydney [(https://www.houzz.com/photos/infinity-blue-contemporary-pool-sydney-phvw-vp~2640344)

Decking was the most expensive add on in our pool project and we definitely went over budget. However we enjoy it every day and hopefully will live here to enjoy a long time. So perhaps keep in mind how long you will live there, what is your budget and then choose whatever you both prefer in this hardscape decision. HTH