Pay to win situations are those where you pay with real money stuff in game that are boosting your stats/ships so in ED you can't buy anything of those so is hardly an situation of p2w. Those are purchasable ingame after playing and grinding, is like saying Anaconda is pay to win because is much more powerful.
As for engineers, is a pain gathering all the stuff that you need and the most painful is the lack of personal storage. I only got FSD upgrade to lvl 4 for my ASP and Python, unlocked lvl 5 but I will not start grinding for lvl 5 mats any time soon, and clean drive to lvl 3 but with only lvl 1 mats so I will not get the lvl 3, just lvl 1.
If you unlock lvl 5 to something at an engineer, every upgrade that engineer have will be unlocked at lvl 5 also. So, as DragoonKnight said and is a good idea, use materials for lvl 1 to raise to lvl 3. As an example, at Felicity engineer I had 21 sulphur and I got to lvl 3 just by researching lvl 1 (clean drive upgrade). You need 3 (sulphur) for going from lvl 1 to lvl 2 and around 15 or 16 (sulphur) to go from lvl 2 to lvl 3. After that all have purchasable commodities that you can buy for lvl 3 and lvl 4 (ofcourse you still need to gather other materials but in this way you are not grinding for all materials that are required). So, go for any research an engineer have using lvl 1 materials until lvl 3, after that go for the easy ones, no matter which recipe. After you get to lvl 5, go for recipe that you want.
It sounds easy, but again the lack of personal storage is a real pain. Is it worth it? I guess so, my Python is great now for long range smuggling just with lvl 4 FSD range and lvl 1 clean drive upgrade, I dont even have to use mines and I only use 3A shield. So if you are ready for some days of wasting time for this, go for it, tho myself I will not get any upgrade soon until we have some sort of cargo storage.