Other than the issues mentioned elsewhere re: HR/Payroll complications, our biggest issue is finding junior talent and facilitating individual growth. For the most part we skew towards people who have some amount of remote work experience, which means skewing towards more experienced team members. That can have some knock-on effects that need to be managed: more experienced typically means greater salary, fewer juniors means less visible organizational structure around things like "I manage and mentor a team of 5" which can be disorienting for new hires, and can limit mentorship growth for senior team members.
For many senior developers, those knock-on effects could be viewed as positives, but we need to be sensitive to the overall composition of the team.
I haven't seen any greater motivational issues at remote-first vs a traditional management position. Like most any job, your motivation is largely a factor of your engagement. It's just as easy to drift on-site, with smoke breaks, lunch breaks, ping pong matches, chatting with your officemates about last night's NBA finals, etc etc.