I've been running OPNsense as a VM in Proxmox for a year on an AliExpress box that doesn't have ECC. If I might ask, why do you have a requirement for ECC?
Before this box, I ran a Dell R230 with pfSense but got tired of the noise and 40 watt power draw.
I've had zero issues without ECC, so I'm just curious about your need for it.
Going to reiterate the above message, you want a KVM. The one I use by Tessmart or something like that has worked great for me for 4 years now. The model I chose let's me do dual monitors for each laptop docking station I have plugged in (work & personal). They are a US company so you'll need to find one that delivers to your area.
My personal favorite is the people that say it is a hair on fire emergency but then you can never get a hold of them to fix the problem.
I love telling whiny users who claim they've always had "this" problem that I cannot fix what I do not know is broken. If there's no ticket, then nothing is broken, so quit your whining.
Granola, peanut butter, chocolate chips & honey. All mixed together in a sticky mess that is tasty. Make too much? Throw it in the fridge and have a cold tasty snack the next day!
The random aches and pains you start waking up with are here to stay. Learn to embrace them.
And drink more water.
I practice this same thermal battery idea as well with an extra tip of having a couple of fans on timers (sun up to sun down) that sit on the floor and blow the cold air up. It makes a significant difference, especially if you can sit a fan where the cold air from the AC falls to the ground.
I gave it a very short search back when it broke last year. I went with the cheapest way to get it back up and running which was just convert it to a desktop. She never goes anywhere with a laptop in the first place so there was no need to make it portable again.
She's retired and just used it to surf the web. A Chromebook would work perfectly for her if she was not dead set of having Excel for her recipes and bill tracking.
I did not want to deal with the remote IT support of it all, so I plugged in a mouse/keyboard and a second monitor to make it more like a desktop PC setup, lol.
This happened on a decent spec'd HP laptop I bought my mom a couple years back. No easy way to repair without ordering new hinges that were impossible to find and the PC repair shop quoted over $500 repair on a $700 laptop when it was new.
Now she just leaves the laptop open in the 180 degree position with the laptop being held into a stand & bungie cord strapped to it to prevent it from falling foward. It is now a desktop PC and no longer a laptop.
This is old information for me & I have done no further research outside of probably 5-10 years ago when I used this site.
I think I am going to be one of the people buying into Zen 5 but mainly for the longevity of the platform aspect. I'm in the preplanning stage of my next ProxMox server that will be my NAS (unRAID VM), local infrastructure (Samba AD, Adguard, etc.) & Gaming PC via Parsec/Moonlight or plugged directly into the PC with GPU/NVME passthrough to a VM for gaming.
Firewall is on a separate ProxMox host so if the ProxMox host needs a reboot internet will be fine.