I also have a son in MAG level 4. I don’t try to figure out whether the bonuses are worth it or not for my kid. I think that’s a decision that’s best left to his coaches.
There was a thread on Protec grips a long time ago: https://chalkbucket.com/threads/reisport-protec-vs-reisport-traditional-leather-grips.20005
My son uses regular (non-HyperProtec) Reisport grips. His coach said the HyperProtec ones are good for older gymnasts, but not good for younger ones.
Here are a few clubs with competitive gymnastics programs in that area: TuS Hornau, Eintracht Frankfurt, SGK Bad Homburg, TV Hofheim, TSG Münster, TV Langen, TSV Heusentamm, TuS Eintracht Wiesbaden, KTV Wetzlar, TTS Frankfurt. Depending on what level you are looking for, there are a lot more...