Welcome to the club!
The build sounds good, and yes a little bit overkill. I host way more on much older gear, comfortably. For "homelab" stuff I wouldn't buy a Xeon like the other commenter said lmao, you're not going to like your bills. That's way too overkill as you're mostly likely going to be memory-bound, not CPU-bound.
Just for reference, I have ~65 containers running and using ~8 GB RAM. I started with 8 GB and added another 8 GB to have a bigger buffer, and to try out new stuff from time to time.
In general, don't worry about hardware too much, get what is within your budget to build up knowledge and skills. You will figure out what you need later down the line.
Also, I prefer Adguard Home over Pi Hole, and check out Vaultwarden, the community Rust version of Bitwarden as well.