So the mod first lets normal ores dry out and then replaces them with infinite ones. What are the advantages of doing this over just replacing them with infinites from the start?
If i understood correctly, it will be possible to make it so the infinite ores have the same mining speed as normal ores?
Does it have any effect on Oil deposits (I know one other endless resource patches mod that would force oil richness to 100%, wondering if this mod does the same)

So the mod first lets normal ores dry out and then replaces them with infinite ones. What are the advantages of doing this over just replacing them with infinites from the start?

When a resource tile is depleted, there’s an event that fires for it, allowing me to just instantly start working with that resource tile, avoiding running a search on chunk generation and gathering them all together, and then running the same exact code on each found resource tile. While the UPS savings I’m sure isn’t much, it could probably add up if there are a lot of chunks being generated (from artillery fire, etc).

It additionally allows for better compatibility with mods that override the default resource generation and add the resources in during the same code block (like RSO does) without having to be aware of them (current and future) and adding optional dependencies to force code execution order.

If i understood correctly, it will be possible to make it so the infinite ores have the same mining speed as normal ores?

Yes. So, in update 0.17.65, infinite ores where changed such that (using the example the devs gave) a 260% resource tile will give 2 ore + 60% chance of a 3rd per mining cycle. By this mod replacing the ores the way it does, it allows you to mine at the vanilla 1 ore per cycle rate until gone, and then it’s replaced with a 100% resource tile, so it can never mine more than the 1 per cycle (until you start researching productivity bonuses). And only at this point will depletion (if you enable it) take hold and start yielding less than 1 per cycle (another advantage of replacing as they deplete vs all at once during generation).

Does it have any effect on Oil deposits (I know one other endless resource patches mod that would force oil richness to 100%, wondering if this mod does the same)

No. Any tile that is already infinite (like oil) is completely ignored. It will not force its percentage yields onto resource tiles that don’t belong to it. (I had noticed what you mentioned with other mods as well and it annoyed me.)

Hope that helps to clear things up!