I am a newer player, playing since February 2019, have now nearly a billion and the largest ship I own is a DBX. I have 3 Engineers (Martuuk, Farseer and McQuinn). My focus is Exploring, I will try other things. I have now access to Sol and Achenar. I also have long since traveled more that 5000 ly from start (Palin).
As I see it, engineering is implemented just as a time sink. While a bit of effort should be required to use this system the 'effort' on the player side is implemented with no effort from Frontier. I could buy an Anaconda, easily, and have money left for rebuy and equipping it. But what would I do with this thing? Without heavy engineering this thing is a sitting duck.
I plan to buy a Python but could not bring myself to do it, because of engineering. Equipping it A-rated is no problem (have access to Shinrata, Elite in Exploring) but engineering is a problem, even with the 3 Engineers I have. Also I planned to buy an Imperial Courier (have the rank), but without engineering this ship is nothing special. My Viper MK4 can do the same...
From my point of view:
Engineering can be divided into engineering for jump range, speed (mainly thrusters and FSD) and common advantages (Fuel Scoop, Scanners,...) and into combat abilities. Combat abilities totally unbalanced the game. I am probably not very good in combat, I do not like PvP and combat. I am 'Novice' in combat and like it that way, because interdictions and enemies have fairly low rank. The last thing I need is Fdevs effortlessly G5000 engineered battle Anaconda every time. I also avoid combat missions. So I would be happy to engineer only for ship abilities and defense.
Engineering starts with unlocking the Engineer, and this is either quite easy, or a real PITA. Take Liz Ryder, I have the invitation of the Blue Mafia and 'friendly' standing with them. And now I should deliver 200 tons of landmines. 200 tons!!! (What she would do with 100.000s ton of this crap is not explained, because there can be no rational explanation). Obviously the 'designer' of this PITA thought, that people who like smaller ships should have a lot of patience (13 flights in my Viper Mk4 with 16 tons cargo space), or that they have to buy a bigger ship for this nonsense alone. This is a huge downturn.
Other unlock processes are similar: Mining 500 tons of ore and then give 10 tons of Painite is not so bad, could even be fun. But 25 modular terminals are a PITA again, because there is no way to collect them in a small ship! I have 16 tons available, and I would like to do the missions needed with this ship. But since I cannot store modular terminals won, I either need always to fly and deliver them (a lot of flying around) or a bigger ship to collect and store them. The amount of senseless items to deliver should be lowered, so that you can collect and deliver this in one go with a small ship. As it is several engineers are a PITA just to unlock them. It is not hard, just a time sink with senseless actions and no fun at all.
The materials situation is discussed in a long thread here recently. I am not talking about all the G5 materials, but this is a point too. But even looking at G1-G3 materials, the situation is not good. I have collected over 5000 raw and manufactured and over 1000 data materials, and are full in certain G5 materials. And have not seen a lot of G1 or G2 materials, not even once! There is problem with the distribution, it does not follow the 'rarity' grade, it seems skewed. Looking for materials could be fun, if it worked. But it does not. And visiting material traders is no fun at all, when you know you will be cheated out of valuable resources just to get something you should have found long since.
The problem with engineering is, that is unimaginative implemented, is designed as a pure time sink to hold up 'power gamers', and solutions like this always turn down people like me.
The second problem is, that engineering becomes more and more a must, not an option. I could live with light engineering, if things would work fine without it and if engineering would be optional. But it is not. There are ships which make no sense without engineering (if you believe the posts here). Especially the PP is often much too small and must be engineered to grade 1 at least. Combat clearly requires engineering even in PvE, in PvP you need probably months to collect materials and engineer your ship to have a chance, even if you are a good pilot in combat.
So engineering is a huge downturn for me. Parts of it could be fun, but the pressure to do it at least in small ways after buying a new ship is huge, and leads to me not to buy new ships, because I do not want to go to this PITA. And so I often stop playing at all for days or weeks, because I have planned several 'progressions' with new ships and new things to try, but engineering always stops me. It was a grind for the Imperial/Federation ranks, but it was doable. But the entire unlock/collect materials process needs to be redesigned from the start, because it does not work correctly and it is so clearly a time sink and no fun in many parts, that it serves not as a mechanism to hold players in the game, but rather a mechanism which drives players away. It is much more fun to collect crap in Fallout 4, the situation is similar, but you easily find enough of this just playing the game, there is no need for 'collecting expeditions' and you can even buy them, even if they are very expensive. This is how a in game mechanism should work!
So - no, sadly I do not enjoy engineering. There are too many obvious and actually insulting time sinks just to delay your progress, too many broken mechanisms and too many things that are pure PITA, intentionally implemented to stop power gamers. Frontier obviously absolved themselves from the need to explain in game mechanisms in terms of the game and so there are bizarre and silly things (like 200 ton of landmines and other nonsense) without even trying to explain them, and this ruins the game world and the immersion. The designer of this atrocity should be forced to read a most basic D&D game master manual, where dire warnings are given against this kind of 'game design/play'.
The funny and creative parts of engineering are hidden behind walls of grind and PITA, just from the start and the unlocking process, and even more with the broken 'material gathering'. Every few weeks threads are started and growing here about the problems to find certain materials, many of them not even 'rare'. If one day I stop playing completely, engineering will have a huge part in this decision...