I have the Spectra S2 also and find the Momcozy M5 gives me the same output.
I second the Momcozy m5!
Spectra has a handsfree kit
https://spectrababy.co.uk/products/spectra-handsfree-shield-cups-pack-of-2?srsltid=AfmBOoqTaMljSWhUmxYuLlhLAMOR-nTdRUqjOa1OK9LZYwT7IMlYo3P-
I really like the momcozy s12 pro
I have the mommed ones which are pretty affordable especially if you can’t them during a sale