Glad you're enjoying it!! 💖 We're about halfway through the main game/monogamous LI routes right now, and if I'm optimistic it'll be like 3-4 years until I've completed that, so the polyamorous routes are pretty far away. They're not really a priority tbh, it's just something I think will be interesting to add after the game has finished as a bonus. I haven't even started plotting them out (though I obviously have some ideas!).
And yes, transferring save files is definitely possible! You could download your save files with "Save to files" in the save menu (at the very bottom), then email those save files to yourself or use a USB or something, and then load them in on your new laptop with "Load from files"!