I find (and please remember I haven't got the years of experience of members here, um, shooting wise that is

) that most things in life are a compromise. I want a Ferrari but can only afford a mondeo. In reality a mondeo is more than suitable for my needs, but if I had the money I would have the Ferrari. Because I can, rather than because I need it.
I know a number of people, one of whom I respect greatly and he has been shooting deer with a 6.5x55 for years and it is a standard off the shelf. Mind you it was probably the higher end of the off the shelf when he got it.
The debate goes into the do you actually need it because of the improvement or do you want it because you can afford it. The good old fit for purpose. Maybe the money would be better spent on taking some lessons ans punching holes in paper until you can outshoot the rifle and then consider the custom route
I started looking at customs because of the price of a left hand rifle and for the money difference between a custom and a left hand rifle it was looking that it might be worth considering.
I spoke to a one custom maker and my spec was; .223 light rifle for traipsing the fields, max 2/3 shots as it was for foxing so light barrel, mainly shooting between 150 and 250 yards. My very extreme range with lots of practice would be 450 yards but unlikely to reach that for a number of years as I personally feel that is beyond my ability and wouldn't want to risk it.
He specced a heavy barrel and an AI stock because I would want to shoot 1000 yards

. After I told him I wouldn't. I worked out the weight and figured that 15 minutes lugging it around the field would be enough for me. ( He was the exception)
Of course the problem for the custom rifle maker is interpretating what the customer wants. Look at any job description and go for an interview. The 2 rarely are the same. So a "good" custom builder is going to have to spend some time trying to figure out that what the customer wants, is actually what he really needs. And sometimes life would be so easy except for customers
If I heart and lung a deer the target point is 4", so if I can hit consistently hit 3/4" (I can)then I don't need better. For now I have managed to conclude that it is not in my interest to buy a custom rifle. BUT, in a year or so everything may change. I might decide that paperpunching at Bisley at 1,000 yards is exciting or find that I want to fox at 600 yards. But I will wait until I my abilities or my wallet excel.
But there is definitely a need for custome rifle builders, but only you, the customer can decide if it is going to improve your ability to hit whatever you are aiming at.
Are you good enough to warrent it? At this stage I don't think i am.