I could reiterate all the methods one could employ to gather engineering materials while simply playing the game, but the instant gratification crowd usually ignores those methods because "Queen" (I want it all, and I want it now). While I agree that building a base stock is a challenge for a new player (but not impossible), once you've reached a certain routine in the game, acquiring engineering materials is only a problem if you want to engineer a ship (or worse, multiple) from zero to hero in one go. Or if you're fixated on one activity, preferably one that requires all things G5 (PvP), an refuse to do anything else.
What I do reiterate is this: The last time I relogged for any materials or data was years ago. My data bins are flowing over, raw materials are trivially easy to acquire, and I get all my manufactured materials from normal gameplay (mission rewards). I hardly ever run into the situation where I cannot at least partly do the engineering I want to do. And remember kids: Full G5 rolls are a myth. It's a fairy tail completionists tell their kids as bed time stories when they want them to grow up to be a grindlord.
So I've taken a break from playing with the main account, and decided to finally make use of my alt, who is basically starting from zero.
Been running missions out of Sol for a bit of Federal (ugh!) rank, varying them to keep it fun. Bit of courier work, some assassinations, bit of covert stuff here and there, all using a Python with all multis and a wake scanner. Leaving the stations I'll take the 30 seconds or so to buzz about scanning wakes, and have filled my bins with the G1-G5 wake mats including the legendary datamined wake exceptions. I'll target anything in front of me while in supercruise, picked up a shedload more mats that way. Got over 50 Pharmaceutical Isolators from blowing up the dangerous/deadly Anacondas that interdict me in the higher threat missions. When I drop into a system that's in a state of some sort, I'll often scan the nav beacon and visit some High Grade Emissions if they're convenient and not out of the way. A few encoded ones too if I feel like it. Did one trip out to the shard forests (which I actually enjoy doing) and augmented here and there by visiting some of the brain tree sites. (again, actually enjoy doing)
So all in all, without having to resort to the youtuber tactics, I've been able to engineer the few ships the alt has to a reasonable degree, unlocked about half the engineers so far (only guardian unlock has been the FSD booster and shield booster), and while my mats bins aren't full to the brim but fine for another couple of ships I plan on snagging to round out the fleet. Toss in a trip up to Rackham's Peak a few weeks ago for a booze cruise which funded a carrier, and after a couple of weeks of off again on again play where I just pay attention to what I'm after and play the game normally, I'm much further along than I expected to be and - more importantly enjoyed doing it.