I’ve never used Krita, but I did use Gimp and you’re right: There definitely is a learning curve. Maybe it’s time to try Krita now

I once was surfing in Portugal as well, in Ericeira. Really beautiful over there.

Did you surf before? Because two sessions a day sounds a lot if you’re just starting out.

Good shoulders and back muscles is a beneficial I’d say. And generally good core strength. Enjoy your trip! :)