Dispite the characteristic Maciavellian input from Peter Dutton
, spending time collimating, adjusting mirror holders or secondary spacings, improving tube stiffness, having new secondary baffles designed and made, flocking inside of tubes or yes... eeeven fiddly shimming of focuser orthogonality
etc......it is all tinkering. So don't feel alone that your low cost rig has needed some time on it, because there are many $100k+ rigs that have needed some too, so good on you for sticking with it and trying
Mike