I was pissed how Dollhouse achievement is somehow "protected" (the internal function simply didn't work inside a loop/hook/timer and so on), compared to others in achievements library, so I have found a way around it - as usually.

GMod - Dollhouse achievement unlocker

-- Whatever I have tried... It just simply did not increment Dollhouse achievement, it seems it is "protected" in some awkward way.
-- See: https://imgur.com/a/mT7aA

--local DollhouseID = 25

--[[hook.Add("Think", "Dollhouse achievement unlocker", function()
    if achievements.GetCount(DollhouseID) < achievements.GetGoal(DollhouseID) then
        achievements.SpawnedRagdoll()
        print(achievements.GetName(DollhouseID), achievements.GetCount(DollhouseID) .. " / " .. achievements.GetGoal(DollhouseID))
    else
        timer.Simple(1.0, function() hook.Remove("Think", "Dollhouse achievement unlocker") end)
    end
end)]]

--[[timer.Create("Dollhouse achievement unlocker", 0.01, 0, function()
    if achievements.GetCount(DollhouseID) < achievements.GetGoal(DollhouseID) then
        achievements.SpawnedRagdoll()
        print(achievements.GetName(DollhouseID), achievements.GetCount(DollhouseID) .. " / " .. achievements.GetGoal(DollhouseID))
    else
        timer.Remove("Dollhouse achievement unlocker")
    end
end)]]

-- Other failure attempts...
-- lua_openscript_cl ... include ... fuckin' achievement still doesn't want to increment! ...
-- .......

// 13 minutes later, I have figured how to get around it. Copy and paste the following line into console (while in-game, preferably singleplayer instead of multiplayer), several times:
sv_allowcslua "1"; alias "unlock_dollhouse" "lua_run_cl achievements.SpawnedRagdoll()"; lua_run_cl for _ = 1, achievements.GetGoal(25) - achievements.GetCount(25) do RunConsoleCommand("unlock_dollhouse") end


// Enjoy your new stats,
//  CaptainPRICE.