KEF to Blue Lagoon

Hey all,

We land at 15:50 PM in May at KEF and we need to take public transportation/taxi. We do not have checked in luggage (only cabin luggage), what is the economical way to reach Blue Lagoon from KEF?

I saw that FlyBus operates only at 730 AM so that is not an option.
The only option I see is the Destination Blue Lagoon that leaves at 16:30 which will cost 2 of us around 60 Euros to reach the lagoon.

Is this the best way or would there be another way that is cheaper that you would be aware of?
Thank you, I searched past posts. I saw Hyfill Taxi but it seems to be quite expensive for two people. Maybe I see something wrong on its website but I believe it is 300 Euros (I know I am seeing something wrong)

https://www.hreyfill.is/en/airport-blue-lagoon-reykjavik/