nevermind, this is the real fix

lovely/fixes.toml

@@ -534,4 +534,24 @@ if effects[ii].h_chips then
     update_hand_text({delay = 0}, {chips = hand_chips})
     card_eval_status_text(effects[ii].card, 'chips', effects[ii].h_chips, percent)
 end
+'''
+
+# Fixes Steam API not loading on unix
+[[patches]]
+[patches.pattern]
+target = 'main.lua'
+match_indent = true
+position = 'after'
+pattern = '--To control when steam communication happens, make sure to send updates to steam as little as possible'
+payload = '''local cwd = NFS.getWorkingDirectory()
+NFS.setWorkingDirectory(love.filesystem.getSourceBaseDirectory())
+''' 
+
+[[patches]]
+[patches.pattern]
+target = 'main.lua'
+match_indent = true
+position = 'before'
+pattern = '--Set up the render window and the stage for the splash screen, then enter the gameloop with :update'
+payload = '''NFS.setWorkingDirectory(cwd)
 '''

src/core.lua

@@ -19,8 +19,8 @@ NFS = nativefs
 -- respects symlink/.. combos
 NFS.setWorkingDirectory(lovely_mod_dir)
 lovely_mod_dir = NFS.getWorkingDirectory()
--- ! Changing the CWD here causes the Steam API to fail on some UNIX platforms (#345)
--- NFS.setWorkingDirectory(love.filesystem.getSaveDirectory())
+-- make sure NFS behaves the same as love.filesystem
+NFS.setWorkingDirectory(love.filesystem.getSaveDirectory())
 
 JSON = json
 
@@ -33,6 +33,7 @@ local function set_mods_dir()
         if lovely_mod_dir:sub(1, #love_dir) == love_dir then
             -- relative path from love_dir
             SMODS.MODS_DIR = lovely_mod_dir:sub(#love_dir+2)
+            NFS.setWorkingDirectory(love_dir)
             return
         end
     end

version.lua

@@ -1 +1 @@
-return "1.0.0~ALPHA-1223a-STEAMODDED"
+return "1.0.0~ALPHA-1223b-STEAMODDED"