You'll need a public IP. CGNAT won't do, unless you'll also add Tailscale (or such) in all your client devices (which might actually be OK).

Grab an old laptop from a junk heap. Ask around for discarded computers. Possibly get an old dead Android (possibly with a broken if barely functional screen) and install Termux. Buying stuff is not green. A laptop with a 5-second battery life, completely broken screen and nonfunctional keyboard will be perfectly good for self-hosting - temporarily plug in an external screen + keyboard, until you get SSH up and running. The rest of access will happen over SSH anyway.

Install your favorite Linux distro (I like NixOS. Debian would be a good basic yet powerful choice).

Set up a webserver (nginx is a solid choice). Serve some static files in LAN.
Make your webserver accessible to the internet. Get a TLS certificate for it, for free, from Letsencrypt. Host a blog. Set up Vaultwarden and import existing passwords into it.

At this moment, your possibilities widen up - many, many services are commonly set up behind a reverse proxy (nginx the webserver is going to decrypt the TLS, then proxy the plaintext connection to your services, so your actual service doesn't need the hassle of TLS encryption). For example Nextcloud.

Set up a Snikket server and install Snikket app in your smartphone (Dino works well on Linux). Tell your significant other, or family, or the closest friend that this is a fallback communication channel in case your main one ever goes down. Set up a STUN/TURN server and start video calling each other.

Email is a hassle. I self-host it, along with an authoritative DNS server and several other things, but it's not for the faint of the heart.

i self host media primarily, but because I self host media, i self host other stuff too. Find where you can improve your life with self hosted apps, then self host them.

I reccomend you start with a vps, local pc is possible but in any case(in my personal experience at least) you'll need a public IP anyways(which is hella expensive for personal use). In any case, you'll have to get a vps. I suggest you check out Contabo. Good prices, pretty ok for hardware related things. I'd suggest you start Nextcloud, a website, very basic stuff. If you are planning to use a local pc, be advised that power will be a big factor. Unless you want to have to pay a lot on your electricity bill, avoid hosting too many things on your local pc(unless you want to have full control over your data, but I personally think if you apply basic cybersec principles, a VPS is fine). I do understand though, despite that it's not fully reccomended, I want to locally host my own mail server to have full control. It comes down to personal preferences and how much control you want.

Here's a thing I'm going to try this weekend:

https://www.aliasvault.net/

Most of my hardware I picked up at the local school board surplus. Also don't ever throw anything out. Old desktops or laptops, you can put Linux on anything. Eventually I bought a 2 bay NAS on sale. Started with surplus server spinning rust drives, then upgraded to shuckable WD drives on a Black Friday. It takes a while but eventually your network becomes a server farm. Patience is the best way to build it. Other resources are office surplus on eBay too. Have fun, try different distros. Check out different flavors of Ubuntu, Mint, Debian and even Nix. everything you do is building your skills. Do you know a neighbor getting rid of an old Mac? Try it all out!