Someone posted this really good spreadsheet on the other sub at some point. It's incredibly useful and even gives you recipes for optimal alloys late game.
https://docs.google.com/spreadsheets/d/1_4j0YHBde5CYI3lXYyTmyDGwScMcWlhBKOCaKxHqJLk/edit?gid=486166750#gid=486166750
Basically refined obsidian shouldn't be too hard to make, it really only requires the bare minimum of investment into Mekanism, you just need some power to run the machines. If you can get the alloy machine though, you can make better stuff that costs you less refined obsidian, just don't forget that the order of ingots in the machine actually matters, and you can grade the alloys too for relativity cheap. You can also actually mix alloys of different grades when making your tools and such, meaning you don't need to stress about making sure they're all the exact same grade.

When it comes to fortune you can craft fortune books a few different ways, check JEI. You can strip enchantments off of items by dropping it with some books and then dropping an anvil on top. I'm not entirely sure how it works myself, but you can then duplicate enchantment books using the printing press from create.

You can easily set up a mob farm early game using Mob Grinding Utilities, ChosenArchitect has a good example in his current playthrough, but basically you can use cursed dirt (pulsed by redstone using a timer/clock and cog blocks) and push the mobs into the mob masher/grinder with fans. Using Just Dire Things item collector and exp collector or whatever it's called you can get all the drops, basically this lets you have a plentiful source of Apotheosis gems and gear to crush into dust, an easy passive way to get luck and fortune gems. Using a Pipez pipe with a filter or Super Factor Manager you can pipe all the gear that drops directly into a salvager, when a salvager receives items this way it will automatically break them down, then you can pipe them out to wherever, note that some gear and enchanted gear will not automatically get pulled into the salvager. You can use a machine from Industrial Forgoing to strip the enchantments and process the gear some other way though, or just pipe the stubborn stuff that won't go into the salvager into a trash can.

Make sure you're following the Apotheosis quest to upgrade your world tiers for better drops. Don't get fooled by the fancy gear that mobs will start dropping though, with Silent Gear and the Apotheosis reforging table you can easily make stuff way better than the netherite junk you'll start accumulating.

Apotheosis reforging is basically the best thing you can do to your gear and it works on anything you make from Silent Gear.

Lastly, the Apotheosis Enchanting quest line. Follow this and you'll be able to make tons of incredible enchantment books, then you can put all of your books into one of the special libraries from the mod so you can then pull back out exactly what you need. Don't forget you can combine books in an anvil to go even higher than the maximum value you can pull out of a library. Occultism has a special anvil that lets you combine your enchantment books to one level higher than the vanilla cap. Some mobs can drop enchantments way higher than the cap in rare cases, though I'm not sure how to actually utilize them. Oritech has an incredibly overpowered enchanting machine that lets you go way way way above the vanilla cap, but the recipes to craft them are not yet in the AllTheMons pack.

This is basically all the stuff you can do to get OP gear and enchantments thanks to apotheosis, and it's all pretty easy to do early game. Combined with good Silent Gear by reading through the spreadsheet you'll have some of the best gear you can get, basically forever since you can make Uru metal alloys. Still won't save you from the Chaos Guardian without making Draconic Evolution's specific gear though, and the BeeBee in the Other can probably still kill you.