A good chunk of the communities I joined appear empty or sparsely populated, even though I can still follow their updates in other parts of the fediverse (kbin, squabbles etc.). Pushing refresh does nothing. Needless to say, that makes for a very unappealing Frontpage. Might it have something to do with the instances I've blocked or is it something else entirely? Thank you!
I also live in a country where WhatsApp is the messaging app almost everybody uses. You won't be able to get all of your relatives, friends and co-workers on Signal, so I'd suggest you start small - get SOME people onboard, make it very clear you're gonna be using WhatsApp for work-related stuff only, see what happens. Besides, Signal has its quirks, too - switching phones and backing up will lead to a lot of frustration and its devs proudly state that "more options is never the answer". It'll sadly remain a niche app for activists and the privacy-inclined, I fear. But if you really care about privacy, you should ditch Telegram ASAP.