As they can't actually see or feel the workplace and the enthusiasm the team is having, you need to encourage their every effort. You literally need to make them feel that they are part of the team and what they are doing even though no one is watching them to do those, it actually matters
Start with hiring the right people, who are already motivated. Who on their own time like to learn and build new things.
Set clear goals and expectations.
Be a strong and decisive leader.
No one is motivated to follow someone who can't make a decision or is unable to provide clear direction.
Having clear, actionable feedback is important. But it's also equally important to reward success and highlight wins.
Also, as a remote team, we organize periodic in-person meetings. While remote work is here to stay, nothing replaces a good face-to-face interaction.
You can never motivate people. Even money is a short term boost. T
he best way is to find out what they want to achieve in 6months or 2 years, and help them achieve that through your company.
Sustainable motivation is intrinsic.
Also, recommended to have weekly 1-1 meetings and team meetings to gauge where they are, emotionally, and professionally.
let them learn and improve, and let them get together if they want in person engagement. Some need it, some dont and are inspired by the isolation. Variety is a truth, and giving space for it will never hurt you in this context