If you’re willing to endure 3 days of falling over like a fly swat, whilst learning, snowboarding is a lot easier on the knees. I tore a lateral cruciate on the first day of a springtime, boarding holiday (I was off piste and the nose of the board dug into the heavy snow at speed, it stopped but I kept going, still attached and some stretching occurred. Stick with me, it does get better). I could barely walk but with some strapping from a bandage, I could snowboard all day without pain.
I skied (alpine) for years and then got into snowboarding, but for the last few years I’ve really got into cross country skiing. No queues, very cheap passes, cheaper gear, the warmest, most comfortable boots ever, the list goes on. You don’t have to go off like the folk in the Olympics, you pick your own pace and level of technique and off you go. It’s also surprisingly easy on the knees too, which is why you see some very old folk still getting around. Not very exciting I hear you say? Not at all, I’ve skied and boarded some very extreme slopes in Europe and Canada, non of that compares to the trepidation of a slight incline with massively long, skinny skis, attached only at the toe. 😬. Brilliant fun!