I like treating my online identities the same as emails: personal, work and anonymous. Depending on the platform I then choose a specific direction for each account.
On Instagram I have two accounts: photography focused and triathlon focused. I only post photos that reflect those activities.
On YouTube I also have two accounts: one for watching all kinds of random videos and one for watching work, or personal development videos. This helps YouTube algorithm serve me better recommendations based on the mode I’m in: relaxing or working.
On Facebook I only have one, because it is tied to my actual identity. I use it only to stay in touch (contact list) with friends and family. I rarely post there though. It is a great tool to wish Happy Birthday though.
On Reddit I have two accounts: personal and anonymous. I use personal for posting travel photos, anonymous for everything else.
For me, there are clear benefits of having multiple accounts. I do hope I’m that switching between accounts keep getting better.