Inconsistent playback of 4k UHD across devices and apps

[fuelraccoon12]

Having trouble playing back 4k UHD Blu-ray rip (MKV) of Friends across multiple devices. I mention the series as I believe the source files are pretty loaded with content (raw, 4k, HDR, 10-bit, etc). Tested specifically against a single file to minimize variables but seeing same behavior across the series. Some devices / apps playback clean while others are stuttering at predictable spots / intervals - 5 seconds, 7 seconds, 36 seconds, etc. Playback info when available usually shows dropped frames at those times. After collating my troubleshooting it appears anything 'Direct Streaming' is stuttering. What is that telling me? 

Since I don't know what all of my clients may be capable of, I'd like for my Jellyfin server to do the heavy lifting. Expectation is that any (most) devices / apps will be able to play media, whether it's native (raw) or transcoded server-side -- or get as close to that as possible. Happy to throw more resources at the server if needed, although I think I'm looking at incorrect (transcoding) settings. I don't want to go to each of my client devices and use unique settings or troubleshoot every app for the right setup.

My process is to use MakeMKV, first to backup the disc to SSD, then make MKV against the local file. I've re-ripped the file from the disc and have made an MKV from the local backup, straight from disc, and from the new rip. All have the same hash (mkvextract'd track from container) so source data is good / consistent.

Pertinent info / settings below. What am I missing or how should my expectations be reset?

Jellyfin Server Info:
Windows Install
Server version - 10.10.3
Web version - 10.10.3
Build version - 10.10.3

Windows 10 Pro 22H2 OS Build 19045.5247
CPU: AMD Ryzen 5 3600
RAM : 16gb
GPU: RTX 2060 Super 8GB VRAM
Jellyfin App, Cache, Metadata, Transcode Storage: Samsung 970 EVO Plus
Storage: MS Storage Spaces - 2 Way Mirror
2x WD Red Pro 6tb

NVIDIA Driver: 566.36
NVIDIA CUDA Driver: 12.7.33

Media Info:
Audio
Title: Surround 5.1 - English - DTS-HD MA - Default
Language: eng
Codec: DTS
AVC: No
Profile: DTS-HD MA
Layout: 5.1
Channels: 6 ch
Bitrate: 2368 kbps
Sample rate: 48000 Hz
Bit depth: 16 bit
Default: Yes
Forced: No
External: No

Video
Title: 4K HEVC Dolby Vision Profile 7.6 (HDR10)
Codec: HEVC
AVC: No
Profile: Main 10
Level: 153
Resolution: 3840x2160
Aspect ratio: 16:9
Anamorphic: No
Interlaced: No
Framerate: 23.976025
Bitrate: 45659 kbps
Bit depth: 10 bit
Video range: HDR
Video range type: HDR10
DV title: Dolby Vision Profile 7.6 (HDR10)
DV version major: 1
DV version minor: 0
DV profile: 7
DV level: 6
DV rpu preset flag: 1
DV el preset flag: 1
DV bl preset flag: 1
DV bl signal compatibility id: 6
Color space: bt2020nc
Color transfer: smpte2084
Color primaries: bt2020
Pixel format: yuv420p10le
Ref frames: 1

Devices / Apps Not Impacted
PC - Jellyfin Media Player - Direct Playing
PC - Firefox - Transcoding
iPhone 15 Pro - Swiftfin Player - Direct Playing
AppleTV 4k (A1842) - Infuse Pro - Direct Playing
AppleTV 4k (A2843) - Swiftfin - Direct Playing (Transcode server side log)
AppleTV 4k (A2843) - Infuse Pro - Direct Playing

Devices / Apps Impacted
PC - Brave - Direct Streaming
PC - Chrome - Direct Streaming
iPhone 15 Pro - Jellyfin Mobile (iOS) - Direct Streaming
iPhone 15 Pro - Jellyfin Mobile (iOS), Native Player - Direct Streaming
iPhone 15 Pro - Swiftfin Native Player - Direct streaming

Video Failure
AppleTV 4k (A1842) - Swiftfin - Direct Playing (Expected, 720p plasma)

These are all the same clients (PC, iPhone, AppleTV x2). Different apps, different experiences.