Unless they remove support for local vaults from their mobile apps, you can continue using the classic self-synced method. I sync my 1Password vault across Android and Windows using SyncThing, using 1Password 7 and the legacy browser extension in Firefox. I don't get the inline 1Password prompt in password inputs, but that's the only disadvantage (Ctrl+Alt+\ brings up the password selector anywhere in the OS, not just the browser).
In fact, if you're okay with only editing/creating password entries on your phone, you don't even need to pay for the desktop app, because you can use it in read-only mode. The Android app has no limitation to editing local vaults, and it's pretty rare for me to actually have to set up new accounts these days, so I'm fine doing it on my phone. I considered paying for 1Password X (their online offering), but it's simply not worth $45 per year for that minor convenience. I can't complain at all, because I use 1Password completely for free.
They have, as far as I can tell. Last month I tried to set up a new 1PW installation and exhaustively searched through the app menus - no sign of standalone vault support anywhere.
It's possible that it was hidden because I had previously signed in to my work's 1PW account, maybe, or that it's hidden too well for me to find. I don't know, and would be happy to learn either way.
iirc (it has been a while since I used it), this fits with what I saw. You could do it if you set it up as a local vault at the very beginning, and add a web account on top of it, but if you started with a web account it was not an option at all.
I fully expect that to happen. And it will catch many people unawares when their iOS app automatically updates and prompts them to "upgrade" to the sync service.
In fact, if you're okay with only editing/creating password entries on your phone, you don't even need to pay for the desktop app, because you can use it in read-only mode. The Android app has no limitation to editing local vaults, and it's pretty rare for me to actually have to set up new accounts these days, so I'm fine doing it on my phone. I considered paying for 1Password X (their online offering), but it's simply not worth $45 per year for that minor convenience. I can't complain at all, because I use 1Password completely for free.