Unfortunately it seems that a lot of people are falling for the misinformation being spread by the "RDR2 Spawn Fix" mod. This is not a viable solution to the spawning issue. Since the mod author has been consistently deleting comments that are meant to inform the public about the issues this mod creates, misinformation like this starts spreading wildly.
There have been a few of us that have proven to syyyke that his mod does indeed break many aspects of the game. What this mod does is give you the visual satisfaction of seeing chickens and passengers. This does not fix the inherent issue that creates spawning issues, which is the utilization of incorrect/improper texture compression formats. We have tested this and know its the case because you can take mods such as WhyEm's DLC or EEE, properly compress their textures, and then have a perfectly working game.
If you are forcing low priority spawns to become a higher priority, this does not change the fact that the engine is still starved for resources. If the game does not have enough resources and you are forcing these spawns to happen, it's going to take resources from other aspects of this game. This can result in massive amounts of culling, broken ped behavior, broken ambient spawns, broken random encounters, broken dialogue trees, and broken scene animations/vignettes. Actually, the problems this mod creates are so severe that most of it is easy to replicate.
You can't brute force spawns and not expect there to be any additional problems. The engine is preventing those spawns for a reason. What do you think is going to happen by forcing spawns that the game already had trouble handling? It's now going to have trouble handling a whole lot more.
Chuck's analogy is absolutely 100% correct. Do you think a room is clean if you sweep all the garbage under the table? Obviously not. And that is what this mod does.
There is absolutely ZERO evidence that the streaming method is what causes these issues. However, what there IS evidence of, is texture compression being a primary culprit.
Take a broken mod, change it's install.xml to use filereplacement - the mod is still broken.
Take that same mod, re-compress its textures - the mod is fixed. Whether you use streaming or file replacement.
TTO is a great example of this. It's a 20gb texture mod. Go ahead and use the streaming method, and I guarantee you will not have any issues. If you do have issues, its because of another mod. This is because the mod author actually compressed his textures (using BC7, which is not even the best compression format, but it still works because all of the textures are compressed.
Let's use this mod as an example. A 300mb hat retexture. This will almost always create spawning issues. Change it to utilize file replacement - spawns are still broken. If we properly compress both textures using basically ANY OTHER FORMAT (including BC7), the spawning issues disappear.
This is because during the time where most of these mods were first created, the spawning issue was not well known, so modders were using the fastest/easiest form of compression. No fault on the OG mod authors, as no one really knew anything.
Also, a gameconfig will NOT fix your issues. No matter what. Period. RDR2's gameconfig does not work the same way as GTA 5's. Actually, a majority of the values you can change in GTA 5 have zero affect on RDR2. You can raise resource pools all you want, but the issue will still ALWAYS be present.