Dealing with more than one project at the time

What I love best is to offload everything to a system that it outside my brain. The focus being that I can forget about one project meanwhile I work on another one. And that I should get into a project quickly thanks to the information saved into this system.
I've used trello, jira, or even a drive document per project, depending on the context.
Do you want to use a tool just for yourself or to have other people use this tool too? If this is just for yourself you can start with something simple like trello and experiment as you go! Otherwise you'll need to consult with your team to understand what they are used to do and what they are ok to try.

+1 for notion, in the broad information management space (google docs crossed with airtable).

When I'm concerned about time management between different projects, I find toggl to be an effective and low-friction way to track time.

In terms of personal work habits, I've found explicitly scheduling blocks of time (2-3 hours in duration seems best for me, but YMMV) toward a specific purpose to be very effective. This helps prevent small interruptions and distractions from causing too much context switching. I schedule these on my calendar, then set an end-timer and silence other notifications so that I can stay focused during the scheduled time.

Yes. I rely mostly on my brain to keep all those projects moving along and allocate adequate focus time on each on them, and also I make sure to kill certain projects that simply aren't going anywhere useful.

I use my brain yes, I don't need an app to help tell me what to do.
Each project require different type of tools though, so I have the necessary set of tools for each projects, that include the task mgt part of it, sometimes it's as simple as a Google sheet or doc to capture the list of action items and progress.

Yes, https://notion.so