Ooo dear. Got into a bit of a pickle.
Mods will add things or change things to those original in game Config folder xmls and they need to be written up in a different way. We can pinpoint the exact nodes we want to change or use broad sweeping rules to cover everything. In this case you are attempting to do 2 things:
1. Increase the loot drop bags to 50%.
2. Increase the stay time for loot drop bags to 99999.
Here are a couple of pointers.
ModInfo.xml
<?xml version="1.0" encoding="UTF-8" ?>
<xml>
<Name value="ZbagDropIncrease" />
<DisplayName value="Zbag Drop chance" />
<Description value="Increases drop chance to around 50/50 chance, and extends duration of bag in the game world." />
<Author value="Jeffreylane" />
<Version value="1.1.0.0" />
<Website value="https://www.nexusmods.com/7daystodie/mods/4982" />
</xml>
entityclasses.xml
<configs>
<set xpath="/entity_classes/entity_class[contains(@name, 'zombie')]/property[contains(@name, 'LootDropProb')]/@value">.5</set>
</configs>
As for the loot drop bags, 99999 has the potential to cause a heap of performance issues during a Horde Night. With 50% of eliminations converting to bags, there will be a loot mountain and player performance will degrade. A party on a server will come screaming... ^^
Default TimeStayAfterDeath for zombie bags remains at 1200 seconds for V1.0. That is already 20 minutes with a Horde Night event on a 60 minute day cycle being 15 minutes. Those loot bags will still remain and create a mountain. Good luck with finding the balance for that.
An example of how that is governed in Preppocalypse, but with 120 day cycles in mind, and with default loot drop percentages.
<!-- Zombie Loot Bag Time Stay Extensions -->
<set xpath="/entity_classes/entity_class[@name='EntityLootContainerRegular']/property[@name='TimeStayAfterDeath']/@value">2000</set> <!-- Default is 1200 secs (20 mins) and good for 60 min cycle at (15 min BM) but not 90 (22 min 30 sec BM) -->
<set xpath="/entity_classes/entity_class[@name='EntityLootContainerStrong']/property[@name='TimeStayAfterDeath']/@value">2000</set> <!-- Provides a 3 min 20 sec buffer for 120 min cycle -->
<set xpath="/entity_classes/entity_class[@name='EntityLootContainerBoss']/property[@name='TimeStayAfterDeath']/@value">2000</set>
Spherii, Xyth, and a number of other community members have shared guides and tutorials on how to get modding. It is how I learned, and continue to learn.
https://community.7daystodie.com/forum/39-tutorials-guides/
The ModInfo.xml and XpathModding Explanation Thread will assist.
Once you feel a little more familiar with modding, visit the thread for the Unnofficial Modding Discord and join the Guppy's Discord.