@ireneyoung44 thank you for your reply! The thing is, I have both Outlook and Google calendars which I use on a daily basis, and I'm not really happy how google calendar sync my events from all of them.
GanttPRO (https://ganttpro.com/) is one of the best online planners that allow for preparing advanced schedules without extra effort. You get a handy Gantt chart with dependencies and milestones. Quick and easy. Highly recommended!