Does it matter if data is encrypted ?
If it does, I assume you also roll your own network equipment. If you're worried about surveillance, know that you're far more likely to be targeted at the network port than at your data.
As for the process, the cloud (for storing data) is nothing more than a remote fileshare that someone else keeps running. If you have an up to date copy of your data you can change the process any way you like.
Servers are not free, nor are they fire and forget. Once you setup a server and decide to open it to the internet, you become a target, and you will be found. There are bots scouring the entire ip range of every residential IP network looking for juicy targets, and when they find something they record it for later use. Then when some new 0-day is found for service X that you're running, they don't need to scan, they can just lookup in their database an exploit right away.
I'm not against self hosting, and god knows I've been doing it for decades, but it is very rarely worth the hassle compared to the gains. The power cost alone of running a server is more than the equivalent cost of storing it in the cloud (assuming we're not talking media servers, but regular user created data).
The worst argument I usually see is people self hosting mail for private, completely oblivious to the fact that there are usually 2+ people in a mail thread, and something 68% of the worlds population runs on Google/Microsoft/Apple/whatever, so while you may keep your emails private, if they're targeted for being scanned they have already been so.