You are running the VMs headless right?

Alpine Linux, 200MB in size.

Dietpi - lightweight Debian

Maybe you should look at ProxMox

Manjaro and docker

AntiX, Zorin Lite, or Linux Mint Debian Edition are all pretty lightweight distros and beginner friendly.

Just run Ubuntu server. You don’t want something so stripped down it lacks the basics… that’s more for embedded applications or in some cases containers. Ubuntu runs fine with 512MB of RAM on a 386 from the 1980’s… that’s the magic of Linux.

A good lightweight distro is Arch since you can customize it to exactly what you need. If you go that way and have trouble with installation, ArchFi can help a little.

But as others have said, what you actually want is docker. All of your concerns with it stem from your lack of experience using it. When your only tool is a hammer, it's easy to see every problem as a nail.

What about ProtonOS, very small lightweight, I have 2 VM's running in my VCentre using it, the rest are using Ubuntu.

For the apps you are listing I would suggest simply spending an afternoon learning docker.

Can you explain what you mean with lightweight?

It seems to me, by looking at several of OPs comment that you're running the full desktop OS, with Gnome on it, and honestly that's the reason you get the idle CPU and 1.5GB of RAM usage.

Do you want light weight the real answer is, use the server version of it without the UI.

UnRaid may be exactly what you are looking for. It's similar to proxmox, but UnRaid has a plugin called "Community Applications" where people make pre-configured Docker containers that most of the time only need the user to define a path for saving files (though some do need more configuration).

UnRaid boots from a USB to RAM. So it's hard to get lighter weight than that! You don't even "install" it, per se. You can pop it into a computer with an already installed OS, boot via USB, and then can boot the native OS as a VM in UnRaid, if you want. Then shut down, remove the USB, and reboot to the original OS as if UnRaid never existed. Now there's caveats and pitfalls if you are not careful. Don't go formatting drives if you do it that way or making major changes as it could affect the native OS install if you're not careful. Im just letting you know it's possible.

Using the built-in Docker in UnRaid, those services get dynamic access to the computer's resources and have minimal overhead when idle. VMs, I believe, have more overhead. So this may allow you even more capability on an old laptop.

I've never used Docker before, but I now run Home Assistant, Plex, Immich photo backup, minecraft server, Trilium Notes, Blender, Cura Slicer, and a couple others all as Docker containers. All I did was click install, add path to folders, and then they were up and running!

One of my favorite things about how UnRaid works with Docker is that all your Docker containers are set up to be accessible on your network, by default, and can be viewed on any web browser with access to your network. When I want to show off a little, I pull up things like Blender on my smart tv. It's a terrible user experience trying to use a remote as a mouse, but I'm able to "use" Blender on my TV it I so feel!

But mainly, I like to sit outside on nice days and have access to my computer from any device on my network. I'm working on making things accessible over vpn for me and a few services by reverse proxy for friends. But I'm still learning.

Search UnRaid's Community Applications page for services you run and see how many are already available. https://unraid.net/community/apps

There's also youtube videos on making your own programs available in UnRaid. You can also add personal Docker containers through Docker Compose.

Plus, UnRaid makes settings up VMs very easy. So, if you just want to have a program in a VM for ease of use, you can do that too!

DietPi. I have quite a few VMs running DietPi, very light, simple, "just works"!

I have to reluctantly use Docker which is cumbersome, awkward and confusing in comparison. A DietPi VM is simple and easy to run, use and more importantly, keep backed up. I really hate being forced to use Docker when DietPi exists and works!