I’m doing it exactly like I was doing it on reddit, that is, build up my personal home page with all the communities I want to see then I changed my settings to default to subscribed when opening Lemmy instead of All.
Every now and then I check the list of all communities to see if there’s something new worth following, that way it’s also easier to avoid communities that do a lot of spamming, overwhelming the smaller (more interesting IMO) ones.
Microsoft Teams is the official communication tool for business where I work, no need to use whatsapp tho a few colleagues use it for fluff, as for personal/family, some of my family use whatsapp but I don’t (I use Discord), if we want to talk to each other we use “good old-fashioned” phone calls :D