I have no idea if this is your model, but where I grew up, there were “clubs” in my city described as “Travel teams” which were the teams kids had to try out for and if they make it, they pay the $10k to play, travel, coaching, etc. typically the coaches also were connected to the middle and high school teams as head coaches since their players are in school for 7hrs and training wouldn’t start until afternoon - this obviously made ends meet financially for them with benefits and such.
These travel teams were affiliated with the areas league play where 10-12 age group teams (non-travel teams) played matches every Saturday with reduced fees and typically the coach was a knowledgeable parent; the travel teams would play an age group (2 years) up so the skills were more comparable and fair. These leagues paid for the fields and upkeep and whatnot (14+ leagues x 10-12 teams each was substantial in additional to adult leagues also paying), and it wasn’t beholden to the travel team club to maintain it. As such, there were no free rides/sponsorship on either the travel teams or the regular league teams and all were pay-2-play by the parents or sponsors if a team could land them.
In that setup, if a player later was signed by Dortmund or another pro club, I would not expect them to get solidarity payments in any capacity because the teams/clubs weren’t covering the costs of training/coaching - the families were.