Hi Noob,
Your mini PC is similar to mine.
Mine has an N100 CPU (older than an N150 and a little slower).
The other difference, I am running Ubuntu from 240 GByte nvme SSD.
My videos are stored on an external (USB) 2 Tbyte hard drive.
The nvme SSD is currently 95% empty.
I am using Ubuntu Server 24.04.3 LTS.
The Ubuntu Desktop will consume a lot of space for the GUI applications that you don't need for jellyfin.
I don't have any 4K content.
I have 450 Gbytes of content on the external drive.
Most is DVD (480p) with a little bluray (1080p).
Jellyfin stores the metadata on my internal drive.
I see flymetothemoon posted suggesting you transcode to a RAMDISK.
The ubuntu equivalent is called tmpfs.
I read a thread on this forum where someone calculated that if you are constantly transcoding (24 hours per day) to an nvme SSD you might wear out the drive in something like 10 years.
I can't find it right now, but I don't think you need to worry about wearing out your SSD.
I processed my content using handbrake too.
For bluray I set format to MKV using H.264 codec (more or less the fast 1080p preset).
I use MKV because I want to the option to turn subtitles on for my wife who is hard of hearing.
Playing back bluray content to a chrome browser on Windows 11 with subtitles disabled Jellyfin does remuxing, but not transcoding.
When I turn on subtitles it does transcode.
I enabled hardware transcoding in Jellyfin.
That might help you.
Last comment, is your smart TV connecting by ethernet or WIFI?
If WIFI you should check if it is 2.4 GHZ or 5 GHZ (maybe even 6 GHZ wifi if your TV and router support it).
5 GHZ and 6 GHZ WIFI will be a lot faster as long as your TV is fairly close to your router.
Your mini PC is similar to mine.
Mine has an N100 CPU (older than an N150 and a little slower).
The other difference, I am running Ubuntu from 240 GByte nvme SSD.
My videos are stored on an external (USB) 2 Tbyte hard drive.
The nvme SSD is currently 95% empty.
I am using Ubuntu Server 24.04.3 LTS.
The Ubuntu Desktop will consume a lot of space for the GUI applications that you don't need for jellyfin.
I don't have any 4K content.
I have 450 Gbytes of content on the external drive.
Most is DVD (480p) with a little bluray (1080p).
Jellyfin stores the metadata on my internal drive.
I see flymetothemoon posted suggesting you transcode to a RAMDISK.
The ubuntu equivalent is called tmpfs.
I read a thread on this forum where someone calculated that if you are constantly transcoding (24 hours per day) to an nvme SSD you might wear out the drive in something like 10 years.
I can't find it right now, but I don't think you need to worry about wearing out your SSD.
I processed my content using handbrake too.
For bluray I set format to MKV using H.264 codec (more or less the fast 1080p preset).
I use MKV because I want to the option to turn subtitles on for my wife who is hard of hearing.
Playing back bluray content to a chrome browser on Windows 11 with subtitles disabled Jellyfin does remuxing, but not transcoding.
When I turn on subtitles it does transcode.
I enabled hardware transcoding in Jellyfin.
That might help you.
Last comment, is your smart TV connecting by ethernet or WIFI?
If WIFI you should check if it is 2.4 GHZ or 5 GHZ (maybe even 6 GHZ wifi if your TV and router support it).
5 GHZ and 6 GHZ WIFI will be a lot faster as long as your TV is fairly close to your router.