It can be a slow process, up to a year. Riding the bike is great for the knee after TKR surgery. Keep doing that.

I would NOT apply heat to a painful knee. I'd stick with ice. The reason? Heat increases blood flow which increases inflammation which increases swelling and pain. IMO that's bad advice. Heat is very rarely helpful to treat anything as it increases inflammation.

Speaking of inflammation - if you eat a lot of sugar (you may to even be aware), that also increases inflammation. Just check what you eat. And dried fruits are notoriously high in sugar.