Exactly. I would expect a pi to struggle with transcoding. The quality of apps on a lot of smart tvs is poor (particularly older ones that aren't roku or android, and that Samsung is neither).
I bet it would work a lot better on the Samsung if you get an Android TV device (Onn 4k is a good inexpensive one) or roku, if you prefer that platform.
But first it's best to know if transcoding is the problem. It might be direct stream but having network problems.
While something I playing, go to the Plex dashboard for the server. It will show the video and audio stream format/codec. Under each it should say Direct Play. That means it's not transcoding.
Keep the tv dumb. Don't connect it to the internet.
I like to check rtings.com for model specs and comparisons. Like, some panel types work well in a bright room, some work better than others when you are watching with a bright light source behind you. The warehouse clubs (Costco, BJ's, Sam's) tend to have good deals on midrange tvs.
Then pair it with a streaming stick of your choice. A generic Android TV stick/box would work.
Copy on write is the difference. As I understand it, a btrfs snapshot takes no space when it's created (beyond the file system record). The filesystem is always writing changes to file chunks as a new copy of the chunk, which is then recorded as a replacement of the old chunk (which is still present on-disk). So a snapshot tracks all of these later changes, and the file system keeps the old file chunks preserved as long as you keep the snapshot. That's why you can mount a btrfs snapshot. It just shows you the volume through the lens of all of these saved changes.
When you delete a snapshot you are then marking these preserved chunks as free space. So that is also quick.
They offer Windows 10 or 11 preinstalled, or you can install it on an expansion storage card.
The expansion cards are connected via usb-c, so there should be no problem with hot swapping.
With what @infinitevalence recommended I think the M700 is a good inexpensive option if you don't mind doing some work on the case to hack in another ethernet port. Something like this would even get you 2.5Gbe: https://www.aliexpress.us/item/3256804495748525.html
It's Realtek, but there appear to be OpenBSD drivers. That exact one will not work with the headers hanging off the back of the card (that end of the card is right behind the power button in the front corner of the PC). But if they were desoldered and replaced with vertical headers it would work perfectly. There might be something similar with different connectors, or a 1Gbe Intel card available.
I have a spare M700 that I just opened up to take some measurements. There is ~4mm space above most of the m.2 wifi card with the drive caddy installed, or ~18mm with the caddy removed. Even with the caddy installed there is that ~18mm open space above the back 5-6mm of the card, so a vertical connector there would work , but would conflict with the install/removal of the drive caddy since it slides toward the front of the case to remove. further modification would be needed to use them together.
At the back there is ~50mm side-to-side space between the fan exhaust and ethernet port. Only 32mm if you only take up the space of the accessory video port. In that width you have ~15mm vertical space (above the row of ports at the bottom), and ~32mm depth (from the inside of the case back to the back of the SATA connector for the 2.5" drive). You would basically just need to enlarge the optional extra video/serial port opening.
You could even fit a multi-port interface at the back, up to 50mm wide. But you wouldn't be able to use the case screw any more since it's in that space. And you would need to cut the tab it screws into off the case's top cover. But the case should still close ok because of the way it slides into place.
Now I'm thinking about ordering that adapter for my own machine to hack in a 2.5Gbe port.
The m.2 A+E card/adapter replacing the wifi card is new to me. Very cool.
Monit for simple stuff and daemon restart on failure. LibreNMS for SNMP polling, graphing, logging, & alerting.
The PC Engines APU2 boards are really great for this in terms of routing performance per watt, but the prices are up. If you can find a used one it might be possible. I use one for routing and a Lenovo ThinkCentre M700 tiny as a server. The M700 is around double the power consumption at idle, but they are both pretty low power. On 120v the APU2 is ~5w, and the M700 is ~10w when idle.
There are a couple of Celeron N2830 fanless mini-pc router options on aliexpress for under €100. It's 2 core vs the APU2 4 core CPU, but it's faster per-core, so it should do basic gigabit routing without too much trouble (the APU can do it with OPN/pfSense, but only with some tuning).
And that's where I think you may have some trouble. I expect OpenBSD will be slower on the network than those FreeBSD-based distributions. And they max out at gigabit on the APU2 platform. But you could always decide later to switch the OS if you need gigabit performance.
Went through a lot of playback apps over the years, and Plexamp is definitely the best of them all. Reliable downloads, good quality, eq settings.
Home Assistant might be worth a look. It's good for home automation and monitoring tasks.
If the playback device (tv in this case) doesn't support the codec used for audio or video it must be transcoded for playback to work at all. If this is the cause it could be the tv doesn't have the right codecs and a standalone device may be better. It depends on the codecs you are using.
Also, if the network connection is slow, it will transcode so that that playback is smooth but lower resolution or quality.
In either case, if the Plex server isn't strong enough it will struggle. You can investigate this on the dashboard as well, it shows a live cpu usage graph.