i think flatpak has done a lot to make this easier, but at the same time... i'll admit i'm not a fan of it (mostly due to random issues).
the way i see it, more distros need something like arch linux' AUR. if an application is reasonably easy to build, it really does not take much to get it into the AUR, from where there's also a path towards inclusion in the official repos.
i don't know too much about other distros, but arch really makes it amazingly easy to package software and publish everything needed for others to use it. i feel like linux needs more of this, not less - there's a great writeup that puts why linux maintainers are important way better than i ever could:
https://web.archive.org/web/20230525163337/https://kmkeen.com/maintainers-matter/
if it's free, you're the product.
signal seems really good right now, with open source clients, but they already show that they'd like to keep the ecosystem locked down by not allowing 3rd party clients. at some point they will need a way to pay for their datacenters, and even if they claim the foundation or whatever is doing well, i can see the pestering for donations getting much worse in the future.
that said, threema is far from optimal too, im still waiting for matrix servers to become solid options. last time i wanted to set up synapse, the only captcha they supported was fucking Google captcha :|