yeah, people say the voice chat app is terrible, but ask yourself this - have you actually tried it? because i have and honestly it isnt that bad. but if you still dont want to use it, its possible to just plug in a headset and go to town. Fortnite does this, so it cant be too hard for the rest of developers to figure it out too.
it isnt even a matter of if later consoles will come to Nintendo Switch Online, its a matter of when. it appears as though a ton of resources from the Classic Edition consoles have been used to make the NES app, so SNES wont be too far behind. the later consoles will no doubt follow soon after. just be patient
you really want a proprietary messaging system? just use discord.