High CPU usage when audio transcoding?

[FuzzyJelly]

Beginning to wonder if it's the file themselves or the server starved for resources. Tried a few A/B tests with 10.9.11 and 10.10.1 and both played fine with no buffering but I:
1) killed docker containers I installed in the last week and
2) tried different media files than my original post

Tests:
10.9.11 | Firefox (131.0.3): https://pastebin.com/5w0zM6kD
10.9.11 | Chrome (130.0.6723.92): https://pastebin.com/fjiMxnV1

10.10.1 | Firefox: https://pastebin.com/PffQLTaZ
10.10.1 | Chrome: https://pastebin.com/5n1vUEV6

Original files that were buffering: https://pastebin.com/9iXA9TpM