Apache has the better open source tooling IMO.
I use both, but at work I prefer apache simply for its relative ease of setting up our SSO solution. There is probably a tool for that in nginx as well, but its either proprietary or hard to find (and I did try to find it, but setting up and learning apache and then SSO was actually easier for me).
That's great actually.
Then I would suggest using used thin clients. They cost around 50€ each, maybe less. You can install a Linux on there and remotely manage them then. They are quiet, small, not energy intensive and mostly have an x86_64 CPU, so software is also not an issue.
They also mostly have HDMI so connecting is not an issue either. If you still buy a Bluetooth remote, they can be handled without a mouse.
Software wise I am not well versed with google slides, but you can probably use kiosk mode in Firefox or chrome and just have the main page with the slides as chosen website.
Okay, let me get your current setup/needs right:
You have multiple rooms with dedicated Raspberry Pis, that each run PiSignage to display automatically forwarding (google) slideshows.
You now want to minimally change this setup to allow people to manually forward slides.
This begs some questions:
In my head the new setup would look something like this:
The Pis stay, as does PiSignage.
A device is added to forward slides (most likely a Bluetooth remote)
Here is where it gets tricky.
On remote press, a menu could be opened, to select uploaded slides and display them via other means than PiSignage. Closing this slide opens PiSignage again.
But having this easily maintainable is tricky and it will get hacky and people will forget closing their slide and so on.
Alternatively USB-sticks could be used.
Inserting one opens the folder, a slide can be selected with the remote and removing the stick opens PiSignage.
Both methods are hacky and not easily maintainable. But I can not think of other means.
Also I think that you should first think about some means of uploading and selecting slides as well as whether you even want to keep using PiSignage.
The gearwheel on the bottom right has options for language and resolution.
This is also in part true.
Today I was searching for multiple things regarding jinja2 and was always recommended a site that no longer exists, as top result, mind you.
No they didn't and they still don't really do that.
There are too many things (nowadays?) where you have to literally write a question on reddit, stack overflow or Lemmy or the likes and explain your situation in minute detail, because what you find online through search engines is only the standard case which just so happens to not work for you for some odd reason.
Believe me, when I say that, because I always try search engines first, second and third, before even thinking of using some bs-spitting AI, but it really helped me with two very special problems in the last month.
You could also set up a jellyfin (for media) or gameyfin (for games) container, expose that to the internet and give them credentials.
The forgejo discussion is great and has an overlooked detail. The reason the Dutch government wants to switch:
/ Gi: ICC having their MS accounts blocked
The even funnier thing is, that it most probably has, but it prompt injected itself with the word "recommended".
In short: a management web interface.
It has a lot of tools, you may find helpful when working remotely or with a headless setup.
You're one of today's lucky 10,000.