@Timmy83 - As others have stated, good-to-great can be subjective, but wanted to weigh in with what has helped me, and might be applicable based on your experience and comments thusfar
In general, it sounds like you pretty much have the brew day components down, with maybe the exception of water chemistry. I tend to agree that this
can be a key factor in going from good to great, but since I've never had a glass of water at your house, I couldn't tell ya for certain
One relatively cheap and easy experiment you
can do is to brew a batch with RO/bottled water with some basic mineral additions - that will at least give you a view of "I can't tell the difference" or "oh, man, I can't believe my water was an issue this whole time!". From there you can decide on the water testing, adjustments, etc.
Two key things I keyed in on from your description of your process:
1: Fermenting at 68 degrees ambient temp with no cooling. You didn't really comment on what in particular you would consider "not great" about your beer, but this was a red flag for me. Fermenting at 68 ambient means your wort/beer-to-be is probably getting up to 72-75 depending on how active fermentation is, especially in the first few days, which can produce some significant off flavors for most ale yeasts. You say you're not looking to drop a lot of cash on the process (totally get it), but there are some very cheap options like swamp coolers you could leverage here to counter that fermentation temperature rise. (Swamp cooler meaning a simple cold water / ice bath to sit the fermenter in, and a tshirt or cloth wrap around). I would try doing this for at least the first few days of fermentation to keep that temp spike down in the mid 60s. I would look up the yeast you're using and see if you are getting any of the off flavors commonly associated with the strain fermenting at higher than ideal temps.
2: Kegging - Great! As others have mentioned, oxygen exclusion can be a big factor. If you're not doing closed transfers and/or filling with starsan/co2 purging your serving keg this could make a big difference. Lots of vids out there on how to do this with a basic carboy or better bottle as well as other fermenter setups. I don't have any experience on how to do pressure transfers with a bucket fermenter, hoping others can comment there. I doubt you'll see much argument that reducing O2 exposure on racking makes for a better beer, it's just a matter of degrees.
Lastly - you didn't really comment on fermentation, cold crash and ageing times. There was a considerable difference in the quality of my beer after I gave them an extra week in primary (2 to 3 weeks) and at least a full week of cold crash time. I get fairly hung up on having a nice clear beer (depending on style of course) but I would definitely consier patience as my #3 on the list.
Hope that helps!