Selfhosted virtualisation learning kit

Hello Lads and Ladettes,

I'm reaching out to ask for your help and to know your opinion. Currently I have a simple setup of RPi 3 that only serves as a DNS (pihole). I've read some of your posts and I got hooked. I also started playing with HyperV on my Windows PC and created a virtual linux machine (Arch btw for meme purposes).

I have started thinking... What if I bought RPi 4B (8GB RAM) and use some kind of a hypervisor to selfhost DNS and DHCP (pihole), VPN, SSO and maybe even NAS (some kind of platform like plex?).

It's all for learning purposes, so I'm not aiming for anything extra expensive, reliable or ultra-fast. I know the basics, though I'm still a beginner. I thought the RPi 4B would be a good choice as it's relatively cheap and not energy-hungry.

My questions are: What do you think about it in general? Do you know any alternatives to VMware ESXi that I can use for virtualisation? Any tips and trick you have to share? Do you think that RPi 4B can handle such task?

Maybe you know some good, free, open source VPN and SSO services that you can recommed. For NAS I was thinking about OpenMediaVault but I would also be thankful for recommendations in that regard as well.

Thanks in advance for all the help and healthy discussion. Cheers!

EDIT:

Thank you everyone for sharing your views!

I probably didn't mention pretty important factor which is: I need the device to be as small as possible. My wife won't bear huge butt case lying around and always blowing its fans. Nevertheless, buying used UFF machine is a great idea if I really want to go with virtualisation route. I'll keep my eye on Proxmox as it sounds very promising.

I didn't take into account docker because... I simply forgot about such option. In my previous job my colleague was an infrastructure analyst and often explained me intricacies of his job. Since the company I worked for used VMware that was the first thing that came to my mind. If I decide to buy RPi 4, I'll definitely take docker path.

I've read all your messages and they were pure pleasure to read. Thanks for them once more!