You could try this MyVeloFit, discussed in here: MyVeloFit, Online AI Powered Bike Fit
Haven’t got any personal experience with it.
IMO professional bike fits can help if you’re chasing marginal gains, have some sort of mobility issue, or haven’t got a clue where to start and just feel unconfortable. Or on TT bikes, where position has a direct impact on results. But mostly they are a good money maker…