question 1- what is your rifle actually capable of in your hands on a regular day, not the wallet group best day.
Of the ARs I shoot most, I've had 5 that were consistent 3/4" shooters at 100 yds. (better when I have a good day). I don't have regular access to a longer range. I work up loads there and verify zero, but the rifles were used on reactive targets where I couldn't measure a group, but was very satisfied.
question 2- how and what was used in assembly and reloading of your rifle? ( a guideline if you will)
I don't much care for the brand of the lower/upper. I have JP, S&W, RR and even an old stainless steel DPMS lower. I care about the trigger and barrel. I used JP triggers about from the beginning. I had an adjustable Jard that did well. I like the 3 lb Timney's. There are lots of good triggers out there and I only tried a few (single stage since I grew up on bolts and never spent the time to get used to a 2-stage) and I don't spend big bucks.
Same for barrels - I have not spent big bucks. I've had White oak, Wilson, Blackhole polygonal, a turned down Shilen blank and a couple of tight 223 chambered DPMSs, all in 24" or longer stainless bulls, slow twist since I shoot light bullets. I true the face of the upper, use clamp on adjustable gas blocks, smooth vented free float handguards, A2 stocks with 3 lb lead weights and sling loop cut off, slick side uppers (a little thicker walls and no forward assist) and I debur the feed ramp and locking lugs to save brass. Always use a brass catcher. I've had 223, 223AI, and 20P (the most fun).
Nothing special on loads. Always start with new brass for each rifle, one brand and never mixed with another rifle (except the two 223AIs - they were so identical that brass/loads were interchangable). Brass sorted by weight, dies set up for .001 - .002 setback (I always ran from the magazine), anneal every other firing. Ball powder since I drop charge and load 3000+ per trip, usually AA or Ramshot, mostly Hornady V-Max bullets, Forster BR seating die.
question 3- is it really a useful rifle or is it to fussy to keep going, like a race car more maintenance than driving?
So reliable a caveman could run it. I use Colt or Magpul 20 round mags since I'm always on a bench. I only load 10 and only one mag to force myself to slooooow dowwwwwn. I thought the AI would have feeding issues, but they ran slick. I'd clean the barrels about every 200 rounds if I got a break and only clean the bolt groups when I got home (500-700 rounds per rifle). The only breakdown I ever had (in 35+ years) was a trigger group. It had a lot of mileage and the maker told me it was their first design and they happily replaced it with their improved version (thanks JP). But, since uppers/lowers are interchangable and I always take at least two, I kept shooting.
Now, I'll say my 3 favorite rifles of all time are bolt guns, and I always take and use bolt guns (single shots).
