I can't find any documentation on how to configure a Dedicated / Headless server with this mod installed. It's stuck on 60FPS even after trying to run

/c game.speed = 120 / 60
and
/c game.speed = 2

When I quit and reload the server the settings remain default:

0.613 Script @__GTTS__/data-final-fixes.lua:243: GTTS targeting 60 UPS. Started adjusting speeds by: 1 and durations by: 1
1.520 Script @__GTTS__/data-final-fixes.lua:20: CLAMPED: projectile.duration,  800 -> 255

I'm trying to work around this by copying the client side mod-settings.dat file to the server, and using https://github.com/ehlerst/factorio-mod-settings-converter to convert both mod-settings to json to set this on in the server

"has_quality": false,
"data": {
"startup": {
"gtts-Adjust-GameSpeed": {
    "value": true
},
"gtts-Target-FrameRate": {
    "value": 120
},
"gtts-z-No-Runtime-Adjustments": {
    "value": false
}
},
"runtime-global": {
"gtts-Adjust-DayNight": {
    "value": false
},
"gtts-Adjust-Evolution": {
    "value": false
},
"gtts-Adjust-Expansion": {
    "value": false
},
"gtts-Adjust-Groups": {
    "value": false
},
"gtts-Adjust-HandCraftingSpeed": {
    "value": false
},
"gtts-Adjust-Pollution": {
    "value": false
},
"gtts-Adjust-WindSpeed": {
    "value": false
},
"gtts-Reset-GameSpeed": {
    "value": false
}
},
"runtime-per-user": {}
}

Which seems to work as intended?

0.745 Script @__GTTS__/data-final-fixes.lua:243: GTTS targeting 120 UPS. Started adjusting speeds by: 0.5 and durations by: 2
1.579 Script @__GTTS__/data-final-fixes.lua:20: CLAMPED: logistic-robot.speed_multiplier_when_out_of_energy,  0.2 -> 0.224
1.667 Script @__GTTS__/data-final-fixes.lua:20: CLAMPED: projectile.duration,  1600 -> 255

...

HOWEVER - Modded Achievements are separate from the Vanilla version of the game :(