Trying to be private ironically just going to make it worse and make you stand out. Using a non-default OS, non-default browser, custom settings/blocklists will just make your fingerprint more unique.
I use an android phone but just don't use any other google services - no search, no gmail, no default apps. I do most browsing in tor-browser, so google ads won't correlate with me.
syncthing automtically connects with bunch of external servers automatically. Relays/discovery servers/stun etc. You can disable but they are enabled by default. They connect on first run and before you get a chance to disable - atleast on android. Everything may be encrypted but I still prefer to not connect to external servers
Telegram should have a setting to choose the default (secret vs regular chat) and ask the user on installation. I understand about the backups part but a lot of users may don't care about backups. This will remove a lot of bad mouth on them and also save server resources as they don't have to save secret chats forever. I really like telegram for their cool bot-api, instant-view and channels.
May not be archivy directly. But for example if the web pages use static assets like google fonts, jquery, they will send external requests thus leaking the presence of the self hosted server. Or may be some javascript plugin that phones home.
I use dropbox for saving import documents/receipts/statements. Being early adopter, have 5GB storage. All
I need is a peace of mind that I don't loose important stuff if my computer breaks down or temporarily becomes unavailable. I don't need any other feature. If I had to pay about $10 per year, I would just use it happily. But their minimum plan is >$100. I occasionally use file-requests feature. If it was like pay as you go type, that would be good too. I think reasonable low tier pricing will get them consistent long term revenue.
I use an android phone but just don't use any other google services - no search, no gmail, no default apps. I do most browsing in tor-browser, so google ads won't correlate with me.