null guards go brr

Libraries/Core/Helpers/ProfileHelper.cs

@@ -480,7 +480,7 @@ public class ProfileHelper(
             pointsToAddToSkill *= skillProgressRate;
         }
 
-        if (_inventoryConfig.SkillGainMultipliers[skill.ToString()] != null)
+        if (_inventoryConfig.SkillGainMultipliers.TryGetValue(skill.ToString(), out var _))
             pointsToAddToSkill *= _inventoryConfig.SkillGainMultipliers[skill.ToString()];
 
         profileSkill.Progress += pointsToAddToSkill;

Libraries/Core/Helpers/TradeHelper.cs

@@ -414,7 +414,7 @@ public class TradeHelper(
             (double)assortBeingPurchased.Upd?.BuyRestrictionMax,
             pmcData.Info.GameVersion
         );
-        if ((traderPurchaseData?.PurchaseCount ?? 0 + count) > traderItemPurchaseLimit)
+        if (((traderPurchaseData?.PurchaseCount ?? 0) + count) > traderItemPurchaseLimit)
         {
             throw new Exception(
                 $"Unable to purchase: {count} items, this would exceed your purchase limit of {traderItemPurchaseLimit} from the trader: {traderId} assort: {assortId} this refresh"

Libraries/Core/Helpers/TraderAssortHelper.cs

@@ -92,7 +92,7 @@ public class TraderAssortHelper(
                 continue;
             }
 
-            assortToAdjust.Upd.BuyRestrictionCurrent = (int)assortPurchasesfromTrader[assortId.Key].PurchaseCount;
+            assortToAdjust.Upd.BuyRestrictionCurrent = (int)(assortPurchasesfromTrader[assortId.Key].PurchaseCount ?? 0);
         }
 
         // Get rid of quest locked assorts

Libraries/Core/Helpers/TraderHelper.cs

@@ -441,7 +441,8 @@ public class TraderHelper(
 
             // Null guard when dict doesnt exist
 
-            if (profile.TraderPurchases[traderId][purchasedItem.ItemId] is null)
+            if (profile.TraderPurchases[traderId][purchasedItem.ItemId].PurchaseCount is null 
+                || profile.TraderPurchases[traderId][purchasedItem.ItemId].PurchaseTimestamp is null)
             {
                 profile.TraderPurchases[traderId][purchasedItem.ItemId] = new TraderPurchaseData
                 {