Deutchsland ticket minors Fahr app

I found this blurb on a website about the DTicket.

For people under the age of 18, a legal representative is required, and the purchase can only be made at BVG customer centers.

the purchase can only be made at BVG customer centers.

This is apparently an info from the Berlin BVG and only applies there. At least the Munich MVV shows in its FAQ a workaround to circumvent the (legally enforced) restriction for young people under 18 and to buy the ticket in the MVV app, unfortunately only in German; here is a translation by DeepL:

For legal reasons, only people aged 18 and over can create an account in the MVV Ticketshop. Therefore, a detour is necessary if you want to make tickets available to your child on his or her cell phone:
If you allow your child to log in on their own cell phone with your account data, tickets can be purchased with the child's cell phone using your means of payment. It is important to note that the ticket holder must be changed before the purchase. The "I" as ticket holder in the MVV ticket store always refers to the account holder, i.e. you in this case.
To change the ticket holder, please proceed as follows: Select the desired ticket when purchasing. The ticket holder "Me" will appear at the bottom. Click on it. Now you can add a new ticket holder by clicking on the plus sign at the top right (iOS) or the person symbol with the plus sign (Android), or (if there are already other people in the list) select the desired ticket holder. Then continue with the purchase.

Source (scroll down to "Wie können Personen unter 18 Jahren HandyTickets kaufen?").

Thanks! I found the MVV app this morning and was able to purchase a ticket for my son and turn off the renewal. Yay!