Nextcloud is feature-rich, but a little slower and vastly more complicated than a CalDAV server like Baikal.

Use a hardened-by-default OS like OpenBSD, HardenedBSD, or something similar in Linux.

Uh, can’t you just log in to online banking through a browser? I can.

Don’t use Outlook for non-Outlook email services. Problem solved. I am required to use Outlook for my work email, but I keep all of my personal email separate, accessed with FOSS email clients.

Care to elaborate on the significant downsides?

It involves a learning curve, and some things don’t work like bluetooth and streaming copyrighted movies. But most everything else works. Many things in AUR would not be there, but alteratives exist for those willing to adapt. Setting things up are typically done by editing text files on the command line. This sounds hard, but is actually simple once you get used to it. I tried Qubes last year out of curiosity and found it hopelessly convoluted.

My OpenBSD operating system on my laptop is set to randomize my MAC address at every boot.

OpenBSD

Doesn’t work with Javascript blocked.

Laptop not a server, huh? I am writing this from a laptop running OpenBSD, which is my main work and play machine. Works great.

No.

personal

Decent used laptops are quite affordable. I recently scored one on Ebay for under $100. It runs Linux and everything is snappy.